geologie si paleontologie

NUMBER 49824 DECEMBER 2003

GEOLOGY AND VERTEBRATE PALEONTOLOGY

OF THE EARLY PLIOCENE SITE OF KANAPOI,

NORTHERN KENYA

EDITED BY JOHN M. HARRIS AND MEAVE G. LEAKEY

900 Exposition BoulevardLos Angeles, California 90007

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Contributions in Science, Number 498, pp. 1–132Natural History Museum of Los Angeles County, 2003

GEOLOGY AND VERTEBRATE PALEONTOLOGY OF THE

EARLY PLIOCENE SITE OF KANAPOI,NORTHERN KENYA

EDITED BY JOHN M. HARRIS1 AND

MEAVE G. LEAKEY2

TABLE OF CONTENTS

Introduction ............................................................................................................ 1John M. Harris and Meave G. Leakey

Stratigraphy and Depositional Setting of the Pliocene Kanapoi Formation,Lower Kerio Valley, Kenya ........................................................................................ 9

Craig S. Feibel

Fossil Fish Remains from the Pliocene Kanapoi Site, Kenya .......................................... 21Kathlyn Stewart

Early Pliocene Tetrapod Remains from Kanapoi, Lake Turkana Basin, Kenya.................. 39John M. Harris, Meave G. Leakey, and Thure E. Cerlingwith an Appendix by Alisa J. Winkler

Carnivora from the Kanapoi Hominid Site, Turkana Basin, Northern Kenya................. 115Lars Werdelin

1. George C. Page Museum, 5801 Wilshire Boulevard, Los Angeles, California 90036, USA.

2. National Museums of Kenya, PO Box 40658, Nairobi, Kenya.


INTRODUCTION

JOHN M. HARRIS1 AND MEAVE G. LEAKEY2

The site of Kanapoi lies to the southwest of LakeTurkana in northern Kenya (Fig. 1). Vertebrate fos-sils were recovered from Kanapoi in the 1960s byHarvard University expeditions and in the 1990sby National Museums of Kenya expeditions. Theassemblage of vertebrate fossils from Kanapoi isboth prolific and diverse and, because of its depo-sitional context of fluviatile and deltaic sedimentsthat accumulated during a major lacustrine phase,exemplifies a time interval that is otherwise not wellrepresented in the Lake Turkana Basin. Kanapoihas yielded one of the few well-dated early Plioceneassemblages from sub-Saharan Africa but hithertoonly the hominins, proboscideans, perissodactyls,and suids recovered from this locality have receivedmore than cursory treatment. The four papers pre-sented in this contribution document the geologiccontext and diversity of the Kanapoi fossil verte-brate biota.

HISTORICAL CONTEXT

The Lake Turkana Basin (formerly the Lake RudolfBasin) traverses the western Kenya–Ethiopia borderand has been an important source of Neogene ter-restrial vertebrate fossils since the early part of thetwentieth century (Coppens and Howell, 1983)(Fig. 1). In 1888, Count Samuel Teleki von Szekand Ludwig Ritter von Hohnel were the first Eu-ropean explorers to reach the lake (Hohnel, 1938),which they named Lake Rudolf after Crown PrinceRudolf of Austria-Hungary (1859–89). The subse-quent French expedition of Bourg de Bozas (1902–03) recovered vertebrate fossils from Plio–Pleisto-cene exposures in the lower Omo Valley (Haug,1912; Joleaud, 1920a, 1920b, 1928, 1930, 1933;Boulenger, 1920). This discovery prompted theMission Scientifique de l’Omo (1932–33), whichfurther documented the geology and paleontologyof the area to the north of the Omo Delta (Aram-bourg, 1935, 1943, 1947). Allied military forcesoccupied southern Ethiopia during World War II;vertebrate fossils collected during the occupationwere forwarded to the Coryndon Museum in Nai-robi (now the National Museums of Kenya) and in1942 L.S.B. Leakey (honorary curator of the Cor-yndon Museum) sent his Kenyan staff to collectfrom the southern Ethiopian Omo deposits (Lea-key, 1943). Political unrest in both Kenya and Ethi-opia after the end of the Second World War pre-

1. George C. Page Museum, 5801 Wilshire Boulevard,Los Angeles, California 90036, USA.

2. National Museums of Kenya, PO Box 40658, Nai-robi, Kenya.

cluded further fieldwork in the area for more thana decade.

In the mid-1960s, L.H. Robbins investigated theterminal Pleistocene and Holocene archaeology ofthe southwestern portion of the Lake Turkana Ba-sin (Robbins, 1967, 1972). Robbins let it be knownthat the region also contained somewhat older fos-sils and, in 1966, Bryan Patterson initiated a seriesof Harvard University expeditions to the region be-tween the lower Kerio and Turkwell Rivers. Patter-son’s expeditions focused initially on the Kanapoiregion (1966–67) and subsequently on Lothagam(1967–72). Assemblages from the two localitiesshed much light on the late Miocene–early Pliocenevertebrate biota of sub-Saharan Africa and provid-ed the basis for monographic revisions of elephan-tids (Maglio, 1973), perissodactyls (Hooijer andPatterson, 1972; Hooijer and Maglio, 1974), andsuids (Cooke and Ewer, 1972). The Patterson ex-peditions recovered few primate fossils but docu-mented a hominid mandible from Lothagam (Pat-terson et al., 1970; Leakey and Walker, 2003) anda hominin humerus from Kanapoi (Patterson andHowells, 1967; Ward et al., 2001).

In 1967, a joint French, American, and Kenyanexpedition (International Omo Research Expedi-tion) resumed exploration of Plio–Pleistocene ex-posures in the lower Omo Valley. In 1968, the Ken-yan contingent withdrew from the IORE to pros-pect the northeast shore of Lake Rudolf. The EastRudolf Research Project became the Koobi ForaResearch Project when the Government of Kenyachanged the name of the lake to Lake Turkana in1975. The International Omo Research Expedi-tions (1967–76) and Koobi Fora Research Project(1968–78) recovered a great wealth of Plio–Pleis-tocene vertebrate fossils, including important newhominin material. Monographic treatment of ma-terial from the Omo Shungura sequence was pub-lished in the Cahiers de Paleontologie series editedby Y. Coppens and F. C. Howell (e.g., Eisenmann,1985; Gentry, 1985; Eck and Jablonsky, 1987).That from Koobi Fora was published in the KFRPmonograph series of Clarendon Press (Leakey andLeakey, 1978; Harris, 1983, 1991; Wood, 1994;Isaac, 1997).

During the 1980s, National Museums of Kenyaexpeditions under the leadership of Richard Leakeyexplored the sedimentary exposures on the westside of Lake Turkana (Harris et al., 1988a, 1988b).Small but significant Plio–Pleistocene vertebrate as-semblages included the first cranium of Australo-pithecus aethiopicus (Walker et al., 1986) and a rel-atively complete skeleton of Homo ergaster (Brownet al., 1985; Walker and Leakey, 1993).

2 m CS 498, Harris and Leakey: Kanapoi

Figure 1 Map of late Miocene through Pleistocene fossiliferous localities in the Lake Turkana Basin (after Harris et al.,1988b)

During the 1990s, National Museums of Kenyaexpeditions, now under the leadership of MeaveLeakey, concentrated on the southwest portion ofthe Lake Turkana Basin, discovering new localities(Ward et al., 1999) as well as revisiting Lothagamand Kanapoi. Lothagam was reworked from 1989

to 1993 and monographic treatment of the biotahas now been published (Leakey and Harris, 2003).The Kanapoi locality was reprospected from 1993to 1997 (Leakey et al., 1995, 1998). Hominin ma-terial recovered by the National Museums of Kenyaexpeditions has been described in detail (Ward et

Harris and Leakey: Introduction m 3

al., 2001); other recently recovered vertebrate spe-cies and their geologic setting provide the topic ofthis contribution.

GEOLOGICAL CONTEXT

The Lake Turkana Basin dates back to the earlyPliocene. The present lake is sited in a closed basinthat is fed year-round from the north by the OmoRiver, whose source is in the Ethiopian highlandsand seasonally from the southwest by the Turkweland Kerio Rivers and by other smaller ephemeralrivers. Paleogeographic reconstructions by Brownand Feibel (1991) indicate that, for much of thePliocene, the Omo River flowed through the basinand directly into the Indian Ocean but occasionaltectonic activity disrupted the outflow and resultedin short-lived temporary lakes. After about 1.9 Ma,the history of the region is still not clear. It is pos-sible that the river no longer exited through thesoutheastern part of the basin, yet mollusks flour-ished until at least 1.7 Ma ago, implying that wa-ters of the lake had not become as alkaline as theyare at present. Indeed, mollusk-packed sands arereasonably common until at least 1.3 Ma ago (Har-ris et al., 1988a), so the basin may have remainedopen until this time either at the southern end, oralternatively, the lake may have occasionally over-flowed to the northwest through Sanderson’s Gulfinto the Nile catchment.The Plio–Pleistocene ter-restrial and lacustrine strata from the northern halfof the basin form part of the Omo Group (Brownand Feibel, 1986) and are represented by the Shun-gura, Mursi, and Usno Formations in the lowerOmo Valley (de Heinzelin, 1983), the Koobi ForaFormation on the northeast side of the lake (Brownand Feibel, 1991), and the Nachukui Formation onthe northwest side of the lake (Harris et al., 1988a).The Nachukui Formation extends to the southwestof the lake where, at Lothagam, it overlies the lateMiocene Nawata Formation (Feibel, 2003a). Figure2 lists the members of the Koobi Fora and Nachu-kui Formations in stratigraphic order.

The oldest paleolake recognized in the basin isreferred to as the Lonyumun Lake. It is documentedby the lacustrine sediments of the Lonyumun Mem-ber, which was defined as the basal unit of the Koo-bi Fora Formation (Brown and Feibel, 1991) butalso forms the basal unit of the Nachukui Forma-tion on the west side of the lake (Harris et al.,1988a). The Lonyumun Lake is represented in thesouthwest part of the basin by the upper Apak andMuruongori members of the Nachukui Formation(Feibel, 2003a). The fossiliferous strata from Kan-apoi include a short-lived lacustrine episode thatcorresponds with the Lonyumun lacustrine interval.Feibel (2003b) interprets the fluvial sediments thatenclose the lacustrine phase to have been depositedby the Kerio River and has named the sequence theKanapoi Formation. The Pliocene strata of Kana-poi thus provide the oldest record of fluvial sedi-ments deposited by the Kerio River and include a

deltaic tongue extending into the Lonyumun Lake.They thereby complement the fluvial sediments ofthe Kaiyumung Member of the Nachukui Forma-tion at the nearby locality of Lothagam that wereevidently deposited by the Turkwel River (Feibel,2003a).

PALEONTOLOGICAL CONTEXT

As exemplified at the nearby site of Lothagam (Lea-key et al., 1996; Leakey and Harris, 2003), therewas a drastic change in the terrestrial vertebratebiota of sub-Saharan Africa at the end of the Mio-cene due to faunal interchange between Africa andEurasia, and coincident with the worldwide radia-tion of C4 vegetation (Cerling et al., 1997). TheKanapoi biota, dated radiometrically between 4.17and 4.07 Ma (Leakey et al., 1995, 1998) lacks thelarge mammalian genera characteristic of the lateMiocene at Lothagam—such as the amphicyonidcarnivorans, the elephantids Stegotetrabelodon Pet-trochi, 1941 and Primelephas Maglio, 1970, the te-leoceratine rhino Brachypotherium Roger, 1904,the giraffid Palaeotragus Gaudrey, 1861, and bo-selaphin bovids (Leakey and Harris, 2003). Instead,the Kanapoi fauna demonstrates the first post-Mio-cene radiation of endemic African carnivorans(Werdelin, 2003) and a suite of ungulate speciesthat is less progressive than that characteristic oflate Pliocene exposures in the Lake Turkana Basin(Harris et al., 2003). The Kanapoi fish assemblage(Stewart, 2003b) is similar to but less diverse thanthat from the temporally equivalent strata at Loth-agam (Stewart, 2003a).

Partly because of the widespread nature of theLonyumun Lake, fluvial sediments with vertebratefossils representing that time interval are rare in theLake Turkana Basin. Fossils from horizons imme-diately before and after the Lonyumun lacustrineinterval at the nearby locality of Lothagam havebeen described recently (Leakey and Harris, 2003).A hominin-bearing vertebrate assemblage slightlyyounger than that from Kanapoi has been recov-ered from the Koobi Fora Formation in Allia Bayon the eastern shore of Lake Turkana but thus faronly the hominins have been described in detail(Ward et al., 2001). A few suid teeth from the Mur-si Formation, collected by the Kenyan contingentof the International Omo Research Expedition in1967, suggests that the oldest formation in theOmo Group (de Heinzelin, 1983) is of broadly sim-ilar age to the Kanapoi Formation. There are sev-eral small assemblages that have been recoveredfrom localities south of the Turkwel River (EshuaKakurongori, Longarakak, Nakoret, Napudet, etc.)but these have yet to be fully prepared or studiedin detail.

OVERVIEW

The four papers presented in this contribution treatdifferent aspects of the geology and vertebrate pa-leontology of the northern Kenyan locality of Kan-


Figure 2 Stratigraphic sequence of the formal and informal members of the Kanapoi Formation, the Koobi Fora For-mation and the Nachukui Formation where exposed in West Turkana (WT) and Lothagam (LT); for correlative details,see Harris et al. (1988b: fig. 4) and Feibel (2003a, 2003b)

apoi. However, their appearance together in a sin-gle publication will provide a useful source of ref-erence for this interesting site.

Feibel describes the stratigraphy and erects a newformation for the Kanapoi succession. The environ-mental setting recorded by the Kanapoi sedimen-tary sequence reflects a progression of fluvial andlacustrine systems that overwhelmed a volcaniclandscape. He interprets the vertebrate-bearing flu-vial sediments to have formed part of the KerioRiver system as it entered the Lonyumun Lake justover 4 million years ago. The high degree of land-scape heterogeneity and pronounced soil catenas ofthe Kanapoi setting are indicative of a great mosaicof habitats in the southwestern part of the TurkanaBasin during the early Pliocene.

Stewart describes the nearly 3,000 fish elementsrecovered from lacustrine sediments at Kanapoiduring the early 1990s. The Kanapoi fish faunamainly comprises large piscivores and medium tolarge molluscivores. The paucity of herbivorous fishsuch as mormyroids, Barbus Cuvier and Cloquet,1816, Alestes, and distichodids is a little unexpect-ed. While Barbus Muller and Troschel, 1841, andlarge tilapiine cichlids are scarce in African fossildeposits prior to the Pleistocene (Stewart, 2001),the other groups are represented in the Lothagamsuccession and one would expect them to be pre-sent in the Pliocene lake. The Kanapoi assemblagehas many similarities with that of the MuruongoriMember from the Lothagam succession. However,differences in representation of alestid and tetrao-dontid species suggest either that the Kanapoi la-custrine phase correlates temporally more closelywith the Apak Member in the Lothagam sequenceor that the Kanapoi and Muruongori fish assem-blages sample different habitats. Stewart interpretsthe Kanapoi lake to be well oxygenated and non-saline; the scarcity of lungfish, bichirs and HeterotisRuppell, 1829 all of which were well representedin the Nawata Formation at Lothagam, could sig-

nify an absence of well-vegetated backwaters orbays.

Harris, Leakey, and Cerling document the diver-sity of tetrapods (exclusive of carnivorans) thathave been recovered from Kanapoi. The mamma-lian fauna provides a standard for the early Plio-cene in East Africa, with the cercopithecid, ele-phantid, rhinocerotid, suid, giraffid, and bovid spe-cies providing a link between those from upperMiocene levels at Lothagam and those in late Pli-ocene assemblages from elsewhere in the Lake Tur-kana Basin. Even though the microfauna has yet tobe studied in detail, the Kanapoi mammalian biotais already larger and more diverse than the prelim-inary report of mammals from the slightly older siteof Aramis in Ethiopia or from the Nachukui For-mation members at Lothagam. Kanapoi is the typelocality for the oldest East African australopithe-cine species yet recognized, Australopithecus ana-mensis (Leakey et al., 1995), so the Kanapoi biotais of interest for the information it provides aboutenvironments in which early bipedal homininslived. No taphonomic investigation has yet beenundertaken at the Kanapoi locality but, as pointedout by Behrensmeyer (1991), broad-scaled paleoen-vironmental reconstructions based on the presenceof taxa are likely to be accurate despite the taph-onomic history of the assemblage.

The paleosols from the Kanapoi succession sug-gest a suite of habitats similar to those currentlyfound in the vicinity of the modern Omo Delta atthe north end of Lake Turkana. On the basis oftheir modern counterparts, the Kanapoi herbivoressuggest a relatively dry climate and a mixture ofwoodland and open grassland. However, ecologicalstructure analysis (cf. Reed, 1999) suggests closedwoodland, and thus is closer to the wooded habitatinterpreted for the slightly older hominin Ardipi-thecus ramidus (White et al., 1994) from Aramis inEthiopia (WoldeGabriel et al., 1994). An appendix


by Winkler provides a brief preliminary report onthe micromammals.

Werdelin describes the carnivoran component ofthe Kanapoi biota, which is larger and more diversethan those from most Pliocene localities in easternAfrica and provides a substantial addition to ourknowledge of early Pliocene African Carnivora. Itshares a number of species with the slightly olderLangebaanweg (South Africa) and the slightlyyounger Laetoli (Tanzania), but the overall mixtureof species is unique to Kanapoi. The late MioceneNawata Formation at Lothagam has yielded anumber of carnivorans that were evidently mi-grants from Eurasia. The carnivoran assemblagefrom Langebaanweg also includes a number of rel-ict Miocene forms but that from Kanapoi includesonly forms whose immediate forebears are found inAfrica. Kanapoi, therefore, provides evidence forthe first post-Miocene radiation of endemic Africancarnivorans.

SUMMARY

The locality of Kanapoi is significant in that it hasyielded an early Pliocene assemblage that includesrepresentatives of the earliest East African speciesof Australopithecus Dart, 1925, and the vertebratebiota has the potential for providing a detailed pic-ture of the environments exploited by early bipedalhominins. The assemblage is derived from fluvialand lacustrine sediments that are tightly con-strained between tephra dated at 4.17 and 4.07Ma. Paleosols in the sequence indicate the presenceof terrestrial habitats that are today found at thenorth of Lake Turkana in the vicinity of the OmoDelta. In particular, they indicate the presence of asignificant quantity of grass, given that the propor-tion of soil carbonate derived from C4 plants variesfrom 25% to 40% in the paleosols associated withterrestrial fossils (Wynn, 2000).

Much of the terrestrial vertebrate assemblagewas collected via surface prospecting and no de-tailed taphonomical investigations have yet beenundertaken. Nevertheless, preliminary investigationof the mammalian fossils provides support for theenvironmental interpretations derived from the pa-leosols. Grazing mammals outnumber browsingforms by nearly two to one in terms of numbers ofspecies and by three to one in terms of numbers ofspecimens. The microfauna has yet to be studied indetail, but initial investigation of some rodent spe-cies suggests they represent dry and open habitats(see Appendix in Harris et al., 2003). However,ecological structure analysis of the kind advocatedby Reed (1997) suggests that the Kanapoi assem-blage may instead be indicative of closed woodlandas represented at Lothagam by the KaiyumungMember of the Nachukui Formation or in the low-er Omo Valley by Member B of the Shungura For-mation. This apparent conflict of interpretation hasyet to be resolved but may also be indicative thatthe habitats present in the region during the initial

formation of the Turkana Basin may not be directlycomparable with the modern habitats now char-acteristic of eastern Africa.

ACKNOWLEDGMENTS

This introductory section was compiled at the suggestionof the Scientific Publications Committee of the NaturalHistory Museum of Los Angeles County. We are gratefulto John C. Barry, Francis H. Brown, Peter Ditchfield, PeterL. Forey, Nina Jablonski, Alison Murray, Olga Otero,Blaire Van Valkenberg, Xiaoming Wang, Tim White, andan anonymous referee for helpful comments.

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Received 26 December 2002; accepted 23 May 2003.


STRATIGRAPHY AND DEPOSITIONAL SETTING OF THE

PLIOCENE KANAPOI FORMATION, LOWER KERIO

VALLEY, KENYA

CRAIG S. FEIBEL1

ABSTRACT. The Pliocene sedimentary sequence at Kanapoi is attributed to the Kanapoi Formation, newlydefined here. The formation consists of three sedimentary intervals, a lower fluvial sequence, a lacustrinephase, and an upper fluvial sequence. The entire formation is strongly influenced by paleotopographydeveloped on the underlying Mio–Pliocene basalts, with a landscape of rounded hills and up to 40 m inlocal relief. The lower fluvial interval is dominated by conglomerates, sandstones, and pedogenically mod-ified mudstones. Two altered pumiceous tephra occur within this interval. A sharp contact marks thetransition to fully lacustrine conditions. This interval is characterized by laminated claystones and siltstones,lenticular sand bodies, and abundant ostracods, mollusks, and carbonized plant remains. A single vitrictephra, the Kanapoi Tuff, occurs within this interval. A return to fluvial conditions is recorded first byupward fining cycles reflecting a meandering river system. This is succeeded by deeply incised conglomeratesand sands of a braidplain, capped by the Kalokwanya Basalt. The Kanapoi Formation is richly fossiliferous,and has yielded the type specimen as well as much of the hypodigm of Australopithecus anamensis. Ver-tebrate fossils derive primarily from two depositional settings within the formation: vertic floodplain pa-leosols and deltaic sand bodies. These reflect successional stages in the development of a major tributarysystem in the Turkana Basin during the early Pliocene.

INTRODUCTION

The Pliocene sedimentary sequence at Kanapoi pre-sents a complex record of fluvial and lacustrinestrata deposited over a landscape of considerablelocal relief (up to 40 m) on Mio–Pliocene volcanics.Early fluvial systems accumulated predominantlyoverbank mudstones, with a well-developed soiloverprint, associated with lenticular sands andgravels. A lacustrine phase, the Lonyumun Lake, inthe middle of the sequence is marked by laminatedclaystones and molluskan bioherms, with thick del-taic sand bodies. Following local infilling of thelake, a fluvial regime is again represented. The topof the sedimentary interval is dominated by a thickand deeply incised conglomeratic unit that accu-mulated prior to capping of the entire sequence bythe Kalokwanya Basalt.

Vertebrate fossils are found throughout the sed-imentary sequence, being particularly abundant inthe deltaic sand bodies, but are also found in pa-leosols of the lower and upper fluvial sequences.Fossil invertebrates are common in the lacustrinefacies, though the quality of preservation tends tobe poor. Lacustrine mudstones preserve abundantplant impressions and carbonized remains at sev-eral levels.

Isotopic age determinations on materials fromKanapoi by I. McDougall of the Australia NationalUniversity (Leakey et al., 1995, 1998) establisheda precise chronostratigraphy for the sequence. The

1. Departments of Anthropology and Geological Sci-ences, Rutgers University, 131 George Street, New Bruns-wick, New Jersey 08901, USA.

major phase of deposition is constrained to fall be-tween 4.17 and 4.07 Ma, and the capping Kalok-wanya Basalt is placed at 3.4 Ma. The Kanapoideposits reflect an early stage of accumulation with-in the developing Plio–Pleistocene Turkana Basin.

The geological investigations reported here wereconducted over eight visits to Kanapoi between1992 and 1996. Field mapping and 21 stratigraphicsections are the basis for a formal definition of theKanapoi Formation presented here. Analysis of de-positional environments, postdepositional modifi-cation, and sedimentary architecture are the basisfor a reconstruction of the environmental settingfor the rich Kanapoi fossil assemblage.

BACKGROUND

The sedimentary strata around Kanapoi were firstdescribed by Patterson (1966). He recognized manyof the important features of the local geology. Theinterval he described was predominantly lacustrinein character and comprises the middle unit in thesequence described here. No formal stratigraphicterminology or subdivision of the strata was pro-posed, although a section measuring 175 ft. (53.3m) is mentioned. The first report of a hominid fossilfrom Kanapoi by Patterson and Howells (1967) in-cluded a few additional observations on the geol-ogy of the sequence.

Patterson et al. (1970) discussed the Kanapoifauna, and used the term ‘Kanapoi Formation’ forthe sequence, but provided no descriptions, sec-tions, or type locality. The most detailed geologicalwork conducted prior to the 1990s was Powers’


(1980) investigation of strata of the Lower KerioValley. He provided sections and descriptions of thesedimentary strata at Kanapoi, as well as an inter-pretation of depositional environments and post-depositional modification. Most of the early dis-cussion of Kanapoi centered around attempts todate the sequence, including isotopic age determi-nations on the overlying Kalokwanya Basalt, aswell as biostratigraphic comparisons.

The systematic field work undertaken by the Na-tional Museums of Kenya in the early 1990s, underthe direction of M. G. Leakey, led to important newfossil discoveries, a reinvestigation of the sedimen-tary sequence, and establishment of detailed chron-ostratigraphic control (Leakey et al., 1995, 1998).A detailed analysis of the numerous paleosols in theKanapoi sequence was reported by Wynn (2000).

EXPOSURE AND STRUCTURE

The entire sedimentary sequence at Kanapoi dipsvery gently (;18) to the west. Local depositionaldips, however, can be quite high. These are com-monly 12–158 at some distance above the base-ment, and may reach 458 where sediments aredraped directly over hills in the volcanic basement.Several small faults (0.5–1.0 m offset) occur in thestudy area, and in the southeast, a more significantnormal fault (bearing 3108, down to NE) offsets thesection by several tens of meters. For the most part,however, the sequence is much more strongly af-fected by deposition over pre-existing topographythan by subsequent tectonics.

THE KANAPOI FORMATION

The Pliocene sedimentary rocks exposed in theKanapoi region (Fig. 1) are here defined as the Kan-apoi Formation. The type section of the formation,section CSF 95-8 (Fig. 2), is located in the south-eastern part of the exposures and displays most ofthe major characteristics of the formation. Whereexposed, the base of the formation rests uncon-formably on Mio–Pliocene basalts. The PlioceneKalokwanya Basalt unconformably caps the for-mation. In the type section, the Kanapoi Formationis 37.3 m thick. Some local sections are known toreach nearly 60 m in thickness, and the formationcan be seen to pinch out entirely between the ba-salts to the east and north.

The new formation designation is justified onboth lithostratigraphic and historical grounds. Theformation is mappable and lithologically distinc-tive. Unifying characteristics include the dominanceof paleotopographic influence in sedimentary ac-cumulation pattern and an early basaltic clast dom-inance later replaced by silicic volcanics. The singletephrostratigraphic marker within the formationthat has been geochemically characterized is theKanapoi Tuff (Leakey et al., 1998). The formationis related to synchronic deposits of the Turkana ba-sin farther north, but historical usage, complex re-lationships, and lack of correlative marker tephra

(boundary stratotypes) preclude assignment to anypreviously defined stratigraphic units. The lowerportion of the formation likely correlates with theupper Apak Member of the Nachukui Formationdescribed from Lothagam (Feibel, 2003). The la-custrine interval in the middle of the Kanapoi For-mation is correlative with the lower LonyumunMember of the Nachukui and Koobi Fora Forma-tions (Brown and Feibel, 1986; Harris et al., 1988).The upper sedimentary interval in the Kanapoi For-mation corresponds broadly to lower members ofthe Omo Group formations to the north (Moiti andLokochot Members of the Koobi Fora Formationor Kataboi Member of the Nachukui Formation).

Three tephra units within the Kanapoi Formationhave been isotopically dated. Two devitrified pu-miceous tephra low in the sequence yielded ages of4.17 6 0.03 Ma (lower pumiceous tuff) and 4.126 0.02 Ma (upper pumiceous tuff) (Leakey et al.,1995), while the vitric Kanapoi Tuff was found tocontain rare pumices, which were dated to 4.07 60.02 Ma (Leakey et al., 1998). In addition, theoverlying Kalokwanya Basalt has been dated to 3.4Ma, providing an upper limit on the age of the for-mation. The onset of accumulation is estimated tohave begun around 4.3 Ma. Most of the subcon-glomeratic sequence likely accumulated prior to 3.9Ma, but the sedimentary environments responsiblefor accumulation of the uppermost Kanapoi stratawere likely active up until extrusion of the Kalok-wanya Basalt.

The Kanapoi sedimentary sequence was depos-ited on a dissected volcanic landscape with at least40 m of local relief. This basal topography had astrong influence on the lateral variability of the se-quence and disrupted the sedimentation patternthrough nearly the entire stratigraphic thickness.The lowermost stratigraphic units are localizedwithin paleotopographic lows, while the super-posed strata become more and more laterally con-tinuous upwards. The onlapping sequence of sedi-ments is complex, as the strata were depositedmore-or-less horizontally, against this topographicsurface. The overall stratigraphic sequence of theKanapoi Formation reflects three intervals, an ini-tial fluvial regime, a subsequent lacustrine phase,and a final return to fluvial conditions.

Local basement for the Kanapoi Formation con-sists of Mio–Pliocene basalts. They are typicallyspheroidally weathered, and present a landscape ofconical hills, many of which protrude through theeroding sedimentary sequence today (Fig. 1). Thereis considerable variation in the nature of the con-tact between the local basement and the KanapoiFormation, primarily as a function of paleotopo-graphic position. The most common association,seen in paleotopographic lows as well as at otherpositions, is a scoured relationship, which super-poses basalt cobble- to pebble-conglomerates, orless frequently sandstones, on basalt basement (Fig.2: sections CSF 95-8, 95-10). Slightly higher paleo-topographic positions sometimes preserve a gravel

Feibel: Stratigraphy m 11

Figure 1 Geological map of the Kanapoi area showing prominent geographic landmarks and locations of the stratigraphicsections


Figure 2 Type section (CSF 95-8) and reference sections of the Kanapoi Formation. Numbered correlations shown are1, lower pumiceous tuff; 2, upper pumiceous tuff; 3, basal flooding surface of the Lonyumun Lake sequence; and 4,Kanapoi Tuff. See Figure 1 for location of sections. For a key to symbols, see Figure 3

regolith developed on the basalt, along with ablocky structured paleosol developed on silts orclays (Fig. 4; sections CSF 96-10, 95-13). At evenhigher paleotopographic positions, correspondingto the landscape exposed at the time of inundationby the Lonyumun Lake, molluskan packstones rep-resenting bioherms up to 1 m in thickness are de-veloped on what were then islands of the basaltbasement. The highest of the paleotopographic hillspreserves a pebbly clay paleosol that has been con-tact baked upon extrusion of the capping Kalok-wanya Basalt (east of CSF 96-8).

The initial sedimentary interval of the KanapoiFormation, informally termed the lower fluvial se-quence, can be constrained between the Mio–Plio-cene basalts below and the lacustrine sequenceabove. The base of the lacustrine sequence is a sharpboundary in virtually all sections and is easily rec-ognizable by an abundance of ostracods, carbonizedplant fragments, and/or mollusks. The lower fluvial

sequence is characterized by conglomerates, sand-stones, and claystones with well-developed vertic(paleosol) structure. The conglomerates are generallymassive, basalt cobble to pebble units. Sandstonesare medium- to fine-grained, quartzofeldspathic orlitharenitic, and commonly display well-developedplanar crossbedding in 10–20 cm bedsets. Large-scale trough crossbedding is locally seen in coarsersandstones, while the finer grained sands and upperportions of sand bodies are typically massive due tobioturbation. Mudstones are generally quite thick inthe lower fluvial sequence (up to 10 m; sections CSF95-10 in Fig. 2 and 95-5 in Fig. 5), with well-devel-oped paleosols. Wynn (2000) has provided a detailedanalysis of paleosols throughout the formation. Themost common paleosol is the Aberegaiya pedotype,a thick, often cumulative vertisol with well-devel-oped wedge-shaped peds and slickensided dish frac-tures. This lower sedimentary sequence records a de-positional regime controlled by fluvial systems, and


Figure 3 Key to symbols for the graphic sections presented in this report

there are indications of both braided and meander-ing streams based on internal sequences and primarystructures.

Several tephra units are intercalated within thelower fluvial sequence. The two most prominent of

these display characteristics of airfall tephra thatmantled the Kanapoi paleolandscape. The lowerpumiceous tephra layer is a thick (up to 3.6 m),poorly sorted unit, with altered angular pumiceclasts to 1 cm in diameter scattered throughout.


Figure 4 Reference sections from the basal contact of theKanapoi Formation. See Figure 1 for location of sections.For a key to symbols, see Figure 3.

The upper pumiceous tephra layer is a thinner unit(ca. 15 cm), and displays laminated basal and up-per subunits with an unsorted pumiceous middle.The vitric component of these tephra has been com-pletely altered to clay and zeolite minerals. Both,however, had a significant pumiceous component.The pumices have been devitrified and slightly flat-tened, but appear as clay pebbles dispersedthroughout the units. Devitrification of the pumiceshas left a residual population of volcanogenic feld-spar crystals, which have been used to control forthe age of the strata and associated fossils.

Overlying the lower fluvial sequence and locallybanked against the higher elements of the erodedvolcanic basement is a lacustrine interval. Litho-stratigraphic, chronostratigraphic, and biofacies in-dicators all support correlation of this lacustrine in-terval with the Lonyumun Lake phase well knownfrom the Omo Group deposits of the northern Tur-kana Basin (Brown and Feibel, 1991; Feibel et al.,1991) as well as from Lothagam (Feibel, 2003) andelsewhere in the lower Kerio Valley (Feibel, unpub-lished). Where the volcanic basement produced lo-cal islands in this lake, they are mantled by a mol-luskan packstone, dominated by the gastropod Bel-lamya Jousseaume, 1886. Elsewhere, the lacustrinestrata begin with a mollusk- and ostracod-rich clay-stone, typically succeeded by a well-laminated clay-stone and siltstone sequence, and continue with anupward coarsening sequence, which is capped by

distributary channel sands. The upper portion ofthe deltaic complex has isolated sand bodies, rep-resenting distributary channels. This deltaic com-plex contains the only vitric tuff preserved at Kan-apoi. This unit, termed the Kanapoi Tuff (Leakeyet al., 1998), is a pale brown, fine-grained tuff withwell-preserved climbing-ripple cross-lamination.Upper portions of the tuff commonly show soft-sediment deformation, and in a few localities, thetuff preserves pumice. The composition of thistephra indicates an iron-rich rhyolite (Table 1). Al-though this tephra does not correlate with any ofthe well-known tephra of the Turkana Basin OmoGroup sequence, Namwamba (1993) has suggestedthat it correlates with his Suteijun Tuff of theChemeron Formation in the Baringo Basin to thesouth.

Above the Kanapoi Tuff, lacustrine conditionspersisted locally for a short period. In an importantlocality west of Akai-ititi, a distributary channel se-quence is cut into the Kanapoi Tuff (Fig. 6). Herethe eroded channel base is draped with a molluskanpackstone that includes a well-developed reef of theNile oyster Etheria Lamarck, 1807. The remainderof the channel is filled with a quartzofeldspathicsand. The record of Etheria in a channel settingdocuments the perennial nature of the river at thistime. The transition from the lacustrine interval tothe upper fluvial interval is not sharp, as in the baseof the lacustrine sequence, but rather proceedsthrough an interval of interbedded shallow lacus-trine muds and those with a clear pedogenic over-print indicating exposure. There are also severalmoderate to well-developed paleosols within the la-custrine sequence, indicative of instability in lake-level as well as local emergence due to delta pro-gradation. Wynn (2000) reports several new pedo-types from this stratigraphic interval due to theseparticular conditions.

In most sections, the overlying sedimentary se-quence again becomes dominated by a fluvial sys-tem, and several coarse gravels with significant ero-sional bases cap the sedimentary deposits. This in-terval is referred to here as the upper fluvial se-quence. Like the lower fluvial sequence, this intervalexhibits a high degree of lateral variation (Fig. 7).The influence of the basement topography is consid-erably less, however, and thus the sequence presentsmore characteristic upward-fining units indicative ofa meandering fluvial system. It is noteworthy that,in all but one section, once fully fluvial conditionsare re-established, there is no further indication oflacustrine conditions or even of floodplain ponding.The single exception is seen in section CSF 95-10(Fig. 2). Here a thin interval of ostracod-packedclaystones and fissile green claystones clearly indi-cates deposition in a lake or pond. This interval restson a thin bentonite. It is possible that this sequencerepresents the Lokochot Lake, a lacustrine phase,which occurred ca. 3.5 Ma in the Turkana Basin.The Lokochot Lake is well documented from OmoGroup deposits in the northern Turkana Basin


Figure 5 Reference sections from the lower and middle portions of the Kanapoi Formation. Numbered correlations shownare 3, basal flooding surface of the Lonyumun Lake sequence; and 4, Kanapoi Tuff. Unnumbered correlations are lithologiccontacts walked out between sections. See Figure 1 for location of sections. For a key to symbols, see Figure 3

Table 1 Electron microprobe analysis of glass from the Kanapoi Tuff (Leakey et al. 1998).a

Sample SiO2 Al2O3 Fe2O3 CaO K2O Na2O MgO MnO TiO2 Cl F Zr Total N

KP01-15-01K92-4846K92-4847

70.3669.5069.76

7.867.557.66

8.328.318.42

0.370.280.29

3.930.260.37

1.730.160.24

0.010.010.01

0.250.250.25

0.250.230.24

0.420.520.48

0.030.010.01

NA0.290.28

93.5396.4996.58

61318

a Abundances are shown as weight per cent. N, number of shards analyzed; NA, not analyzed

(Brown and Feibel, 1991; Feibel et al., 1991), andhas been recognized elsewhere in the lower KerioValley (Feibel, unpublished).

The uppermost strata of the Kanapoi Formationare a sequence of massive cobble- to pebble-con-glomerates, which incise deeply into the underlyingfluvial strata. These conglomerates are dominatedby silicic volcanics, with a matrix of litharenitesand. The conglomerates may occur as multipleunits and may reach up to 21 m in thickness. They

often have thin sand interbeds. Mudstones are rarein this upper part of the section, and by the top ofthe formation, the depositional setting appears tohave developed into a gravel braidplain. Thesegravels are overlain by the Kalokwanya Basalt(Powers, 1980). The basalt has been dated to 3.4Ma by McDougall (Leakey et al., 1995). In somelocalities, the basalt fills deep channels cut into theconglomerates.

The vertical and lateral variations in lithofacies


Figure 6 Reference section from the middle portion of theKanapoi Formation. The Kanapoi Tuff here is deeplychanneled, and the channel-fill includes both an Etheriabioherm and a later channel sand. See Figure 1 for loca-tion of sections. For a key to symbols, see Figure 3

Figure 7 Reference sections from the upper part of the Kanapoi Formation. Numbered correlations shown are 1, lowerpumiceous tuff; 2, upper pumiceous tuff; and 3, basal flooding surface of the Lonyumun Lake sequence. See Figure 1 forlocation of sections. For a key to symbols, see Figure 3

seen at Kanapoi are summarized in Figure 8. Thissomewhat schematic diagram emphasizes the ge-ometry of the major facies types and their relation-ships to the underlying basement paleotopography.

FOSSIL CONTEXT ANDPALEOENVIRONMENTS

The Kanapoi stratigraphic sequence is summarizedin the composite section of Figure 9. This compos-ite forms the basis for a discussion of the contextof fossil vertebrate faunas recovered from Kanapoi,as well as for the environmental history recordedin the deposits.

There are two major stratigraphic levels produc-ing the bulk of the vertebrate fossil material at Kan-apoi. The lower level is the channel sandstone andoverbank mudstone complex associated with thelower and upper pumiceous tephra. Most of thefossils in this interval, including much of the Aus-tralopithecus anamensis Leakey et al., 1995, hy-podigm, come from vertic paleosols developed onthe floodplain through this period. The upper fos-siliferous zone is the distributary channel complexassociated with the Kanapoi Tuff. This richly fos-siliferous zone is dominated by aquatic forms (fishand reptiles) but also includes a wide range of ter-restrial mammals. Fossils are also found in the up-per fluvial sequence, where they are associated withboth channel and floodplain settings.

The environmental setting recorded by the Kan-


Figure 8 Schematic drawing of the geometry of major lithofacies and marker beds in the Kanapoi Formation. Note thevertical exaggeration in the diagram. Only major components are depicted, minor facies are shown in white

apoi sedimentary sequence reflects a progression offluvial and lacustrine systems that overwhelmed avolcanic landscape. The fluvial system that domi-nated local environments throughout the Kanapoirecord was the ancestral Kerio River. This is sup-ported by evidence from the tectonic heritage of theregion, provenance of sedimentary clasts, and thesoutherly link provided by correlation of the Kan-apoi Tuff into the Baringo Basin. The ancestral Ker-io River was certainly seasonal through this timeperiod. Perennial flow is only demonstrated for themiddle of the represented time interval, through thepresence of Etheria reefs in a channel setting abovethe Kanapoi Tuff. At other times, there are indica-tors of strong seasonality in flow, particularly inconglomerates low and high in the section as wellas in the prevalence of planar cross-stratification inmany of the sands. This may reflect strong season-ality in a perennial stream or ephemeral flow con-ditions. The well-developed upward-fining cycles,particularly in the upper fluvial interval, however,are suggestive of continued perennial flow there.

The hills/islands of the volcanic basement provid-ed a considerable degree of local heterogeneity. Forthe fluvial systems, this would have been manifestnot only in the local topographic relief but also indifferent soil conditions, drainage, and vegetationpatterns. This is an element of habitat patchiness

which is not typically seen in the Plio–Pleistocenepaleoenvironments investigated from elsewhere inthe Turkana Basin (e.g., Feibel et al., 1991). Thefluvial systems that encountered this complex land-scape were spatially controlled by paleotopograph-ic lows that restricted both the flow patterns forfluvial channels as well as the extent and connect-edness of the early floodplains. Although the degreeof influence this basement topography exerted de-creased through time, it was present throughout theformation.

A strong seasonality in precipitation is docu-mented by the prevalence of vertisols in the over-bank deposits. In this sense, the Kanapoi flood-plains are closely comparable with those of the ear-ly Omo Group sequence (e.g., Moiti, Lokochot,Tulu Bor Members) in the Turkana Basin to thenorth. There does not appear to be a progressiveshift in the character of paleosols through time atKanapoi. Rather, the variability seen in soil typesreflects aspects of the soil catena across the Kanapoipaleolandscape. This relates primarily to topo-graphic effects (including drainage and leaching),soil development on different parent materials, andvariations in the maturity of soils induced by re-organizations of the landscape. Examples of the lat-ter are the influence tephra fallouts produced in thelower and upper pumiceous tephra. The pervasive


Figure 9 Composite stratigraphic column for the Kanapoi Formation. Note major fossiliferous levels in lower fluvialpaleosols and in deltaic sands of the Lonyumun Lake stage. Age control based on work of I. McDougall (Leakey et al.,1995, 1998)


thick profile of the lower pumiceous tephra indi-cates it blanketed the landscape and would haveforced a ‘restart’ of a successional regime in soil,vegetation, and ecological communities based onthis volcanic parent matter. The thinner upper pu-miceous tephra is only patchily preserved, whichimplies that it was locally incorporated into the ac-tive soil substrate rather than overwhelming it.

The Lonyumun Lake transgression produced themost dramatic reorganization of the Kanapoi land-scape. The sharp basal contact of the lacustrineclaystone in this interval demonstrates a rapiddrowning of the landscape. The precise chronostra-tigraphic control on the Kanapoi sequence providesthe best age control on this event, which can beplaced at 4.10 6 0.02 Ma. The Lonyumun trans-gression affected a major portion of the TurkanaBasin (ca. 28,000 km2), most likely due to tectonicor volcanic damming of the basin outlet. The trans-gression was everywhere rapid, and Kanapoi is sit-uated along the drowned paleovalley into which theancestral Kerio River flowed.

The rapid local infilling of the Lonyumun Lakeat Kanapoi is to be expected from the minimal ac-commodation space available in this drowned pa-leovalley and the rapid sedimentation induced byproximity of the ancestral Kerio River Delta. Thethick accumulation of the Kanapoi Tuff (nearly 11m) in the central part of the Kanapoi area resultedfrom the filling of the interdistributary bays of thisdelta (Powers 1980) following an explosive erup-tion in the rift valley to the south. As the lake re-treated northwards, a progression of minor inun-dations and exposure is reflected in the interbeddedfluvial and lacustrine strata that mark the transitionfrom the lacustrine phase to the upper fluvial se-quence.

The characteristics of the fluvial strata that suc-ceeded the Lonyumun Lake sequence reflect theconsiderable infilling that the lake phase producedand the broader floodplains available for a mean-dering river system. In other aspects, however, thisriver was very similar to the system that existedprior to the Lonyumun transgression. This lowerportion of the upper fluvial sequence stands in starkcontrast, however, to the upper strata of the inter-val, where sands and gravels dominate to the nearexclusion of mudstones. This upper portion of theformation reflects two fundamental changes in thesystem, increased supply of coarse clastics and agradual drop-off in overall accumulation rates. Theclastics are dominated by siliceous volcanic cobblesand pebbles, in contrast to the basaltic suite of con-glomerates at the base of the formation. This likelyreflects renewed tectonic activity in the source areato the south. The slowdown in accumulation is im-plied rather than measured, as there are no timemarkers between the Kanapoi Tuff and the Kalok-wanya Basalt. The dramatic change in sedimentaryfacies, however, suggests that much of the time be-tween these two chronostratigraphic markers lieswithin these upper gravels. This upper portion of

the sequence would likely have presented the mostdramatic deviation in environmental characteris-tics. The substrate of the braidplain would havebeen well drained, and the coarse siliceous volca-nics would provide a poor medium for growth ofvegetation. The starkness of this landscape wouldbe succeeded, however, by the truly inhospitablevolcanic landscape produced by eruption of the Ka-lokwanya Basalt.

CONCLUSIONS

The Pliocene sedimentary sequence of the Kanapoiregion, termed here the Kanapoi Formation, wasdeposited by the ancestral Kerio River in threephases. Initial deposition occurred upon a fluvialfloodplain that was broken by numerous hills of thelocal Mio–Pliocene basaltic basement. These hillsstrongly influenced patterns of deposition, as thefluvial system mantled the complex topographywith channel gravels and sands, while vertic paleo-sols developed on the adjacent floodplains. Two pu-miceous airfall tephra accumulated on this land-scape (lower pumiceous tuff, 4.17 Ma; upper pu-miceous tuff, 4.12 Ma), allowing precise chrono-stratigraphic control on this phase of deposition.The Lonyumun Lake transgression replaced the flu-vial system with a lacustrine setting and the rapidlyprograding Kerio River Delta. The vitric KanapoiTuff (4.07 Ma) was deposited primarily in interdis-tributary floodbasins at this stage. The prograda-tion locally replaced the Lonyumun Lake with asecond floodplain system, somewhat less con-strained by basement topography. A shift in thissystem from a meandering sand/mud fluvial systemto a gravel braidplain reflects tectonic activity in thesource area to the south and a lowering of accu-mulation rates. Eruption of the Kalokwanya Basalteffectively ended significant sediment accumulationat Kanapoi.

The rich vertebrate fossil assemblages of Kanapoiare found in floodplain paleosols of the lower andupper fluvial intervals, as well as in the distributarysands of the Kerio River Delta during the Lonyu-mun Lake phase. The high degree of landscape het-erogeneity and pronounced soil catenas of the Kan-apoi setting provided some of the greatest habitatpatchiness recorded from the Turkana Basin Plio–Pleistocene.

ACKNOWLEDGMENTS

Support for this work was provided by the Leakey Foun-dation, the National Geographic Society, the National Sci-ence Foundation (U.S.A.), and the National Museums ofKenya. Special thanks to M.G. Leakey for her enthusiasmand support. I would like to thank Tomas Muthoka forassistance in the field, I. McDougall and J.G. Wynn fordiscussions of Kanapoi geology, and S. Hagemann for helpin the laboratory. Much of the analysis and writing of thisreport was made possible by a fellowship from the Insti-tute for Advanced Studies of the Hebrew University ofJerusalem.


LITERATURE CITED

Brown, F. H., and C. S. Feibel. 1986. Revision of litho-stratigraphic nomenclature in the Koobi Fora region,Kenya. Journal of the Geological Society, London143:297–310.

. 1991. Stratigraphy, depositional environmentsand paleogeography of the Koobi Fora Formation.In Koobi Fora Research Project, Vol. 3. Stratigraphy,artiodactyls and paleoenvironments, ed. J. M. Har-ris, 1–30. Oxford: Clarendon Press.

Feibel, C. S. 2003. Stratigraphy and depositional historyof the Lothagam sequence. In Lothagam: The dawnof humanity in eastern Africa, eds. M. G. Leakey andJ. M. Harris, 17–29. New York: Columbia Univer-sity Press.

Feibel, C. S., J. M. Harris, and F. H. Brown. 1991. Pa-laeoenvironmental context for the late Neogene ofthe Turkana Basin. In Koobi Fora Research Project,Vol. 3. Stratigraphy, artiodactyls and paleoenviron-ments, ed. J. M. Harris, 321–370. Oxford: Claren-don Press.

Harris, J. M., F. H. Brown, and M. G. Leakey. 1988. Ge-ology and paleontology of Plio–Pleistocene localitieswest of Lake Turkana, Kenya. Contributions in Sci-ence 399:1–128.

Leakey, M. G., C. S. Feibel, I. McDougall, and A. Walker.1995. New four-million-year-old hominid species

from Kanapoi and Allia Bay, Kenya. Nature 376:565–571.


Namwamba, F. 1993. Tephrostratigraphy of the Cheme-ron Formation, Baringo Basin, Kenya. UnpublishedM.S. Thesis. University of Utah, Salt Lake City. 78pp.

Patterson, B. 1966. A new locality for early Pleistocenefossils in northwestern Kenya. Nature 212:577–578.

Patterson, B., A. K. Behrensmeyer, and W. D. Sill. 1970.Geology and fauna of a new Pliocene locality innorthwestern Kenya. Nature 226:918–921.

Patterson, B., and W. W. Howells. 1967. Hominid hu-meral fragment from early Pleistocene of northwest-ern Kenya. Science 156:64–66.

Powers, D. W. 1980. Geology of Mio-Pliocene sedimentsof the lower Kerio River Valley. Ph.D. dissertation,Princeton University. 182 pp.




FOSSIL FISH REMAINS FROM THE PLIOCENE KANAPOI SITE,KENYA

KATHLYN STEWART1

ABSTRACT. Over 2,800 fossil fish elements were collected in the 1990s from the Pliocene site of Kanapoi,located in the Turkana Basin, northern Kenya. The Kanapoi fish fauna is dominated by large piscivoresand medium to large molluscivores, whereas herbivorous fish are rare. The genera Labeo, Hydrocynus,and Sindacharax are abundant in the deposits, as are large percoids and catfish. While the Kanapoi faunahas many similarities with both the near-contemporaneous fauna recovered from the Muruongori Memberat nearby Lothagam and the site of Ekora, including the extinct genera Sindacharax and Semlikiichthys,it differs significantly in two features. The Kanapoi fauna is dominated by a Sindacharax species that isabsent at Muruongori and it lacks two other Sindacharax and two Tetraodon species which are commonin the Muruongori deposits and at Ekora. The Kanapoi fauna is similar to that from the Apak Memberat Lothagam, in particular by the domination of Sindacharax mutetii.

INTRODUCTION

The presence of fossil fishes at Kanapoi had beenreported by Behrensmeyer (1976) among others,but no systematic recovery was initiated until 1993.Over 2,800 fossil fish elements were recovered fromKanapoi deposits in the 1993 and 1995 field sea-sons (see map in Introduction, page 2). Most col-lecting was undertaken by the author and Sam N.Muteti, of the National Museums of Kenya, withsome additional collecting by the National Muse-ums of Kenya fossil team. As discussed by Feibel(2003b), the major phase of deposition of the Kan-apoi deposits date from 4.17 Ma to about 4.07 Mawith three sedimentary intervals: a lower fluvial se-quence, a lacustrine phase, and an upper fluvial se-quence. The fish fossils were collected from six siteslocated in the lacustrine phase of the formation,and from one site probably deposited during theupper fluvial sequence and hence slightly youngerthan 4.07 Ma.

Fieldwork at Kanapoi followed three years of in-tensive collection of vertebrate and invertebrate fos-sils from the nearby site of Lothagam (Leakey etal., 1976; Leakey and Harris, 2003), with fossilif-erous deposits ranging in age from late Miocene toHolocene, as well as from the western Turkana Ba-sin Pliocene sites of Ekora, South Turkwel, NorthNapudet and Eshoa Kakurongori. Reference will bemade in this report to the detailed description ofover 7000 fish fossils collected at the nearby site ofLothagam (Stewart, 2003). Collection of fish fossilsat Lothagam was extensive, in order to obtain in-formation on systematics, environment and bioge-ography, previously poorly known from this peri-od. Most fish elements collected from Lothagam

1. Canadian Museum of Nature, PO Box 3443, StationD, Ottawa, Ontario K1P 6P4, Canada.

derived from the Lower and Upper Nawata Mem-bers of the Nawata Formation, and the Apak Mem-ber of the Nachukui Formation, ranging in agefrom 7.44 Ma to about 4.2 Ma (McDougall andFeibel, 1999). Fish bones were also collected fromthe Muruongori Member, and the KaiyumungMember of the Nachukui Formation, which date toabout 4.0 Ma, and approximately 4.0 to 2.0 Marespectively (C. Feibel, F. Brown, personal com-munication). More detailed information about thestratigraphy and geochronology at Lothagam isprovided by Feibel (2003a) and McDougall andFeibel (1999).

Fish collecting at Kanapoi was less extensivethan at Lothagam, as only elements with potentialtaxonomic and systematic information were col-lected. The Kanapoi fish elements derive from sed-iments which date close to 4.07 Ma, and, like theMuruongori Member sediments at Lothagam,were probably deposited during the LonyumunLake transgression (Feibel, 2003b). Reference willalso be made to the fish collected from the Ekorasite, located about 50 km southeast of Lothagamand about 25 km north of Kanapoi, near the mod-ern Kerio River. The Ekora fauna is of Plioceneage and probably also derives from LonyumunLake deposits (Feibel, personal communication).

In the descriptions and discussions below, eco-logical and zoogeographical information on mod-ern fish was referenced from the Checklist of theFreshwater Fishes of Africa volumes (Daget et al.,1984, 1986) and from Hopson and Hopson(1982).

The Kanapoi fishes have not yet been acces-sioned into the collections of the National Muse-ums of Kenya. In the systematic description, thespecimens are listed by the field number for theirsite of origin.


Figure 1 Hyperopisus sp., SEM of isolated tooth, ventralview, from Kanapoi

Figure 2 Hyperopisus sp., SEM of isolated tooth and base,dorsal view, from Kanapoi

SYSTEMATIC DESCRIPTION

Order Polypteriformes

Family Polypteridae

Polypterus Geoffroy Saint-Hilaire, 1802

Polypterus sp.

KANAPOI MATERIAL. 3156, scale.Polypterus material is extremely rare in Kanapoi

deposits, with only one element identified. As Po-lypterus scales, spines, and cranial fragments arerobust and preserve well, this poor record suggestsa minimal Pliocene presence at Kanapoi.

The family Polypteridae is today represented bytwo genera: Polypterus and Calamoichthys Smith,1866 (rather than Erpetoichthys Smith, 1865; seediscussion in Stewart, 2001), both restricted to Af-rica. Most fossil elements comprise scales, verte-brae, and spines, and have been referred to the larg-er and today much more widely distributed genusPolypterus or only to the family Polypteridae.

Polypterus is a long, slender fish with a distinc-tive, long dorsal fin that is divided by spines intoportions resembling sails; they have a lung-like or-gan to breathe air. Polypteridae have several prim-itive features with similarities to Paleozoic paleon-iscoids (Carroll, 1988). Their earliest fossil recordfrom Africa is from Upper Cretaceous deposits inEgypt, Morocco, Niger, and Sudan (Stromer, 1916;Dutheil, 1999). Their Cenozoic record includes fos-sils from Eocene deposits in Libya (Lavocat, 1955);Miocene deposits in Rusinga, Loperot, and Lotha-gam, Kenya (Greenwood, 1951; Van Couvering,1977; Stewart, 2003), and Bled ed Douarah, Tu-nisia (Greenwood, 1973); Pliocene deposits at WadiNatrun, Egypt (Greenwood, 1972); Pliocene depos-its at Lothagam, Kenya (Stewart, 2003); and Plio–Pleistocene deposits at Koobi Fora (Schwartz,1983). Polypterus has never been recovered fromthe Western Rift sites. Two extant species are

known from Lake Turkana—P. senegalus Cuvier,1829, and P. bichir Geoffroy Saint Hilaire, 1802.Polypterus is widespread from Senegal to the NileBasin up to Lake Albert, as well as the Congo Basinand Lake Tanganyika.

Order Mormyriformes

Family Mormyridae

Hyperopisus Gill, 1862

Hyperopisus sp.Figures 1, 2

KANAPOI MATERIAL. 3156, 1 tooth; 3845, 96teeth; 3847, 7 teeth; 3848, 3 teeth; 3849, 2 teeth.

Hyperopisus teeth appear as truncated cylinderswith smooth, relatively flat tops and bases (Figs. 1,2), and attach to the parasphenoid and basihyalbones. The average diameter of the Kanapoi teeth(1–4 mm) is within the range of large extant Hy-peropisus individuals (up to 90 cm total length).

Hyperopisus teeth are relatively commonthroughout the Kanapoi deposits. While absentfrom the Nawata Formation deposits at Lothagam,the teeth are common in the Nachukui Formationdeposits and at the Pliocene South Turkwell site(personal observation). Modern Hyperopisus (andother mormyroids) generate weak electromagneticfields in order to sense their environment. They aretherefore absent from modern Lake Turkana andother bodies of water with high salinity values,which apparently impede this sensory ability (Bea-dle, 1981).

Fossil Hyperopisus teeth (see summary in Stew-art, 2001) are known from Pliocene deposits ofWadi Natrun, Egypt (Greenwood, 1972), fromPlio–Pleistocene deposits in the Lakes Albert andEdward Basins (Greenwood and Howes, 1975;

Stewart: Fish m 23

Figure 3 Labeo sp., SEM of pharyngeal tooth, side view,from Kanapoi

Stewart, 1990), Mio–Pleistocene Lakes Albert andEdward Basins deposits (Van Neer, 1994), from Pli-ocene deposits at Lothagam (Stewart, 2003) andfrom Plio–Pleistocene deposits at Koobi Fora(Schwartz, 1983). Modern H. bebe Lacepede,1803, is known from the Omo River Delta of LakeTurkana, and from the Senegal, Volta, Niger, Chad,and Nile Basins.

Large teeth referred to ?Hyperopisus have beenreported in Pliocene Lake Edward Basin depositsand Pliocene Wadi Natrun deposits (Greenwood,1972; Stewart, 1990, 2001). These teeth, althoughidentical to those of modern Hyperopisus, far ex-ceed the size range of modern teeth, and as no iden-tified bone has been recovered with the teeth, theiraffiliation is problematic. These were not recoveredin the Turkana Basin deposits, and to date have arestricted Nile River and Western Rift presence.

Family Gymnarchidae

Gymnarchus Cuvier, 1829

Gymnarchus sp.

KANAPOI MATERIAL. 3156, 18 teeth; 3845, 3teeth; 3847, 3 teeth; 3848, 3 teeth; 3849, 7 teeth.

Gymnarchus teeth line the premaxilla and den-tary. They are common throughout the Kanapoi de-posits. The Kanapoi teeth average 3–4 mm inwidth, which is within the size range of large mod-ern individuals (60–100 cm total length).

Gymnarchus is piscivorous, although mollusksand insects are also eaten. As in Hyperopisus, thesefish use an electromagnetic field to sense the envi-ronment and are therefore intolerant of highly sa-line waters. Gymnarchus teeth are commonthroughout the Kanapoi deposits, as they arethroughout the Lothagam deposits. Fossil elementsare reported from Miocene–Pleistocene deposits inLakes Albert and Edward Basins (Van Neer, 1994),Pliocene deposits in the Lakes Albert and EdwardBasins (Stewart, 1990; Van Neer, 1992), late Mio-cene and Pliocene deposits at Lothagam, Kenya(Stewart, 2003), and Plio–Pleistocene deposits atKoobi Fora (Schwartz, 1983). Modern G. niloticusCuvier, 1829, is known from the Omo River Deltain Lake Turkana, and in the Gambia, Senegal, Ni-ger, Volta, Chad, and Nile Basins.

Order Cypriniformes

Family Cyprinidae

Labeo Cuvier, 1817

Labeo sp.(Figures 3, 4)

KANAPOI MATERIAL. 3156, 12 teeth; 3845,24 teeth; 3846, 4 teeth; 3847, 37 teeth; 3848, 6teeth; 3849, 26 teeth teeth, 1 trunk vertebra.

Labeo is essentially represented by its pharyngealteeth, which were not identifiable to species (Figs.3, 4). One vertebra was also recovered, and while

similar to Barbus Cuvier and Cloquet, 1816, ver-tebrae, Labeo vertebrae can be distinguished by tra-becular morphology. These elements represent in-dividuals up to 90 cm in total length, which is with-in the modern size range of the Turkana species.

Labeo teeth are surprisingly common throughoutthe Kanapoi deposits. Its teeth are rare in the Na-wata Formation sites at Lothagam, but more com-


Figure 4 Labeo sp., SEM of pharyngeal tooth, ventralview, from Kanapoi

Figure 5 Barbus sp., SEM of pharyngeal tooth, ventral view (left) and side view (right), from Kanapoi

mon in the Nachukui Formation sites. Labeo is aninshore bottom fish, eating algae and organic de-tritus. The fossil record is scanty (Stewart, 2001),but reported from late Miocene deposits at Lotha-gam, Kenya (Stewart, 2003); Pliocene deposits in

Wadi Natrun, Egypt (Greenwood, 1972), KoobiFora, Kenya (Schwartz, 1983), the Lakes Albertand Edward Basins (Stewart, 1990); and Pleisto-cene deposits in the Western Rift (Van Neer, 1994).A reported Miocene occurrence from westernUganda may be in error; the author states that cer-tain Mio–Pliocene sites had Pleistocene-aged fossilsmixed in (Van Neer, 1994:90). Labeo-like teeth arealso reported from the mid-Miocene of Loperot butare not confirmed (Van Couvering, 1977). In LakeTurkana, extant Labeo is represented by one spe-cies—L. horie Heckel, 1846. Elsewhere, the genusis widespread throughout the continent, includingthe Nile Basin, West Africa, eastern Africa, and theCongo and Zambezi Basins.

Barbus Cuvier and Cloquet, 1816

Barbus sp.(Figures 5, 6)

KANAPOI MATERIAL. 3156, 4 teeth; 3845, 2teeth; 3846, 3 teeth; 3849, 6 teeth.

Barbus is exclusively represented by its pharyn-geal teeth (Figs. 5, 6), which represent small indi-viduals, probably under 30 cm total length. Theseteeth do not resemble those of B. bynni Boulenger,1911, the only similar sized Barbus now inhabitingLake Turkana, but do resemble those of B. altian-alis Boulenger, 1900; no other comparison withmodern Barbus species was made. The teeth do nothave the rows of small cusps observed on someBarbus? teeth recovered from Miocene deposits inSaudi Arabia (Otero and Gayet, 2001).

Like Labeo, Barbus is an inshore demersal (bot-tom-dwelling) fish, with a varied diet of ostracods,mollusks, insects, aquatic vegetation, and occasion-ally fishes. Barbus teeth are not common at Kana-poi, nor are they common at nearby Lothagam

Stewart: Fish m 25

Figure 6 Barbus sp., SEM of pharyngeal tooth (differentfrom Fig. 5), side view, from Kanapoi

Figure 7 Distichodus sp., SEM of oral tooth, side view,from Kanapoi

Figure 8 Hydrocynus sp., SEM of oral tooth and base,side view, from Kanapoi

(Stewart, 2003). Their fossil record in Africa is vir-tually nonexistent prior to the Pliocene (Stewart,2001), with the earliest reported finds being fromPliocene deposits at Lothagam (Stewart, 2003), Pli-ocene deposits in the Western Rift, Congo (Stewart,1990), Plio–Pleistocene deposits from Koobi Fora(Schwartz, 1983), and Pleistocene deposits from theWestern Rift (Greenwood, 1959; Van Neer, 1994).Van Couvering (1977) notes that ‘‘Barbus-like’’teeth are known from mid-Miocene deposits inKenya. The report of a probable Barbus in Miocenedeposits in Saudi Arabia (Otero, 2001; Otero andGayet, 2001) indicates these fishes could have en-tered Africa from the Arabian region during landconnections in the Burdigalian (early Miocene) (seediscussion in Otero, 2001).

At present, Barbus is represented by three speciesin Lake Turkana, with only B. bynni attaining alength of at least 30 cm in Lake Turkana.

Order Characiformes

Family Distichodontidae

Distichodus Muller and Troschel, 1845

Distichodus sp.(Figure 7)

KANAPOI MATERIAL. 3156, 1 tooth; 3845, 2teeth; 3847, 2 teeth; 3849, 3 teeth.

Distichodus teeth are oral, lining the premaxillaand dentary (Fig. 7). The average height of the Kan-apoi teeth was 5 mm long, which is within the sizerange of modern individuals.

Distichodus remains are not common at Kanapoinor at Lothagam, but this may reflect their smallsize and probable poor preservation. The fossil re-cord is poor (Stewart, 2001) but is known fromMio–Pliocene deposits in the Lakes Albert and Ed-ward Basins (Van Neer, 1994), Pliocene deposits inthe Lakes Albert and Edward Basins (Stewart,1990), late Miocene deposits at Lothagam, Kenya(Stewart, 2003), and Pleistocene deposits at KoobiFora (Schwartz, 1983). Extant D. niloticus (Lin-naeus, 1762) is known from Lake Turkana andfrom the Nile Basin up to Lake Albert.

Family Alestidae

Hydrocynus Cuvier, 1817

Hydrocynus sp.(Figure 8)

KANAPOI MATERIAL. 3156, 23 teeth, 1 den-tary fragment with tooth; 3845, 33 teeth, 1 dentaryfragment with tooth; 3846, 3 teeth; 3847, 13 teeth,1 dentary fragment with tooth, 1 premaxilla frag-ment; 3848, 32 teeth, 4 dentary fragments, 4 den-tary fragments with teeth, 1 premaxilla fragment;3849, 2 teeth.

Hydrocynus teeth are long and conical in shape(Fig. 8), with considerable size range. At Kanapoi,both teeth and jaw elements were recovered, oftenwith the teeth in situ, usually in replacement sock-ets within the jaw element. Teeth and jaw elements


Figure 9 Brycinus macrolepidotus, SEM of second innerpremaxillary tooth, occlusal view, from Kanapoi; labialside at bottom, lingual at top

Figure 10 Brycinus macrolepidotus, SEM of first, second, third, and fourth inner premaxillary teeth (from left to right)and some outer teeth, occlusal views; lingual side at top right, labial at bottom left; modern specimen

represent individuals of up to 1 m in total length,although modern individuals in Lake Turkana donot exceed 65 cm in total length (Hopson and Hop-son, 1982). Several small teeth with a broader baseand more triangular shape than most teeth weredetermined, from modern Hydrocynus jaws, to beteeth which were just erupting.

The fossil record of Hydrocynus has been pri-marily based on teeth (Stewart, 2001); therefore,the recovery of jaw elements potentially providesnew information about the fossil genus. Hydrocy-nus are pelagic and are voracious piscivores. FossilHydrocynus teeth are known from Mio–Pleistocenedeposits in the Western Rift, Uganda (Van Neer,1994), Miocene deposits of Sinda, Congo (VanNeer, 1992), late Mio–Pliocene deposits at Lotha-gam, Kenya (Stewart, 2003), Pliocene deposits inWadi Natrun, Egypt (Greenwood, 1972), and theWestern Rift, Congo (Stewart, 1990), and Plio–Pleistocene deposits in the Omo Valley (Aram-bourg, 1947) and at Koobi Fora (Schwartz, 1983).Hydrocynus is represented by one species, H. for-skalii Cuvier, 1819, in Lake Turkana, but a secondspecies, H. vittatus Castelnau, 1861, is present inthe Omo River. Hydrocynus is widespread from Se-negal to the Nile, including the Volta, Niger, andChad Basins.

Brycinus Myers, 1929

B. macrolepidotus(Cuvier and Valenciennes, 1849)

(Figures 9–11)

KANAPOI MATERIAL. 3156, 1 second innerpremaxillary tooth.

Brycinus is represented only by a second innerpremaxillary tooth (Fig. 9) which is identical to the

Stewart: Fish m 27

Figure 11 Brycinus macrolepidotus, SEM of second innerpremaxillary tooth, occlusal view; labial side at bottom,lingual at top; modern specimen

same tooth in modern B. macrolepidotus specimens(Figs. 10, 11). Brycinus macrolepidotus has distinc-tive inner premaxillary teeth, which are not foundin other alestid specimens. The tooth represents anindividual of about 30 cm in total length.

A recent study has transferred Alestes macrole-pidotus and twelve other Alestes Muller and Tro-schel 1844 species to the genus Brycinus, leavingfive species in the genus Alestes, and five in a poly-phyletic grouping referred to as ‘‘Brycinus’’ (Mur-ray and Stewart, 2002). Both Alestes and Brycinusare genera within the Alestidae, which possess sim-ilar multicusped molariform teeth. In the followingdiscussions, I will use ‘‘alestid’’ to refer to Alestesand/or Brycinus, but not to Hydrocynus, which isalso alestid but with very different, conical teeth(see Murray and Stewart, 2002, for discussion ofthe terms Alestidae, ‘‘Hydrocyninae,’’ and ‘‘Alesti-nae’’).

Use of fine-meshed screens at several sites result-ed in recovery of many small cusped teeth, whichin the field were thought to belong to Alestes orBrycinus. Closer inspection with a microscope re-vealed that these teeth actually belonged to Sinda-charax, based on similarity to larger specimens (seediscussion under Sindacharax Greenwood andHowes, 1975). The recovery of only one Brycinustooth, particularly when fine-meshed screens (1-mm mesh) were used at several sites indicates thescarcity of this taxon at Kanapoi. Brycinus andAlestes were slightly more common at Lothagam.

The fossil record of Brycinus sp. (and Alestes sp.)is poor (Stewart, 2001), with remains known fromMio–Pliocene deposits at Lothagam, Kenya (Stew-art, 2003), Plio–Pleistocene deposits in the LakesAlbert and Edward Basins (Stewart, 1990), Mio–Pleistocene deposits in the Western Rift (Van Neer,

1994), and Manonga, Tanzania (Stewart, 1997).Miocene teeth with alestid affinities are reportedfrom Loperot and Mpesida, Kenya (Van Couvering,1977). Modern alestids are represented by six spe-cies in Lake Turkana, including A. baremoze deJoannis, 1835; A. dentex Linnaeus, 1758; B. nurseRuppell, 1832; B. macrolepidotus; B. ferox Hop-son and Hopson, 1982; and B. minutus Hopsonand Hopson, 1982. Modern alestids are found inthe Volta, Niger, and Chad Basins to the Nile River,and in the Congo, Zambezi, and Limpopo Basins.Modern alestid species span a range of trophic ad-aptations and habitats. In modern Lake Turkana,they are generally pelagic and omnivorous.

Sindacharax Greenwood and Howes, 1975

A total of 2,272 teeth from Kanapoi are attributedto Sindacharax. This preponderance of Sindachar-ax teeth compared to numbers of elements of otherfish reported here does not reflect actual abun-dance, but a selective collection policy.

Very few Sindacharax dentaries and/or premax-illae are known with in situ teeth, and none fromKanapoi, so identification of isolated teeth was ac-complished by comparison with the complete den-tary and premaxilla of S. greenwoodi Stewart,1997, found at Lothagam (Stewart, 1997). How-ever, because there is considerable individual vari-ation in cusp patterns of teeth in known Sinda-charax jaws, placement of these isolated teeth istentative. Analysis of the in situ teeth and the iso-lated teeth at Lothagam indicated that outer pre-maxillary and dentary teeth were so similar amongSindacharax species, as were third and fourth innerpremaxillary teeth, that no species designations forthese teeth are made. As is the common convention,in this article, teeth are numbered sequentially,starting from the midline of the jaw (#1 left orright) and moving laterally.

As mentioned above in the discussion on modernalestids, many very small teeth (,2 mm) were re-covered, which were initially thought to belong toBrycinus or Alestes, until closer examination indi-cated they were very small S. mutetii Stewart, 2003,and S. lothagamensis Stewart, 2003, teeth. The sim-ilarity in shape and cusping between small Sinda-charax and modern alestid teeth leads to specula-tion on the development of the characteristiccusped ridges in Sindacharax teeth for which thegenus is named (Greenwood and Howes, 1975;Greenwood, 1976). Examination of a range of Sin-dacharax inner premaxillary teeth indicates that,while the smaller teeth (ca. ,2 mm) are cusped, inlarger teeth, the cusps morph to form ridges. Oncethe ridges are formed, the tooth pattern remainsconsistent.

On the other hand, in several of the modern ales-tid specimens observed by the author (including B.macrolepidotus, A. dentex, A. baremoze), the innerteeth remained cusped in both large and small spec-imens, with one exception. Small A. stuhlmanni


Figure 12 Sindacharax lothagamensis, SEM of second in-ner premaxillary tooth, occlusal view, from Kanapoi; la-bial side at top, lingual at bottom

Figure 13 Sindacharax lothagamensis, SEM of first innerpremaxillary tooth, occlusal view, from Kanapoi; labialside at top, lingual at bottom

Pfeffer, 1896, individuals had cusped teeth, but thelarger specimens (ca. 24 cm in total length) hadteeth with ridges (personal observation). Of partic-ular interest therefore is whether teeth of othermodern alestid species develop ridges after achiev-ing a certain length and whether these teeth can bedistinguished from Sindacharax teeth. This leads tosome taxonomic difficulties, as the genus Sinda-charax was erected based on its supposedly uniqueridged teeth. While the analysis of existing Sinda-charax jaw elements demonstrates enough differ-ences with modern alestid elements to keep Sinda-charax as a separate genus, the diagnosis of the Sin-dacharax genus needs to be re-examined in orderto define it more accurately. However, more Sin-dacharax cranial and postcranial elements must berecovered for such revision.

Sindacharax lothagamensis Stewart, 2003(Figures 12, 13)

KANAPOI MATERIAL. 3156, 2 second innerpremaxillary teeth; 3848, 1 first inner premaxillarytooth; 3849, 17 first inner premaxillary teeth, 57second inner premaxillary teeth; 29287, 7 first in-ner premaxillary teeth.

Teeth of Sindacharax lothagamensis are smalleron average than those of other Sindacharax and arerelatively common at Kanapoi. The Kanapoi sec-ond inner premaxillary teeth are identical to boththe holotype and the Isolated teeth found at Loth-agam (e.g., Stewart, 2003: fig. 3.5) (Fig. 12). Thesize range of teeth differs slightly from that at Loth-agam; at Lothagam, second inner premaxillaryteeth ranged up to 5.5 mm in length with most un-der 3 mm, whereas the Kanapoi teeth ranged to 5mm, with most under 2 mm. Numerous first innerteeth were found associated with the second inner

teeth at Kanapoi, particularly at site 3849, and theyshowed a slightly different cusp pattern than thatdescribed for the Lothagam teeth (Stewart, 2003).These Kanapoi first teeth are long and narrow, withthe dominant cusp at the lingual end of the tooth.A smaller cusp, not two, veers in a diagonal linetowards the presumed bucco-labial side, and anoth-er cusp is positioned anterior to the dominant cusp.Anterior to this are one or more ridges traversingthe width of the tooth (Fig. 13).

Sindacharax lothagamensis teeth were the secondmost numerous of Sindacharax teeth at Kanapoi.This abundance of S. lothagamensis is a surprise,as they were primarily recovered in the late Mio-cene Lower Nawata deposits at Lothagam and onlyoccasionally in later Pliocene deposits. Their abun-dance at Kanapoi suggests that absence in laterLothagam deposits may reflect a collection bias ordifferent environmental conditions. Collection biasseems unlikely, as intensive collecting occurred atPliocene deposits in Lothagam. However, differentenvironmental conditions from the late Miocene toPliocene deposits at Lothagam is certainly possible,with the latter providing unfavorable habitats for

Stewart: Fish m 29

Figure 14 Sindacharax mutetii, SEM of first inner pre-maxillary tooth, occlusal view, from Kanapoi; labial sideat top, lingual at bottom

Figure 15 Sindacharax mutetii, SEM of second inner pre-maxillary tooth, occlusal view, from Kanapoi; labial sideat top, lingual at bottom

Figure 16 Sindacharax mutetii, SEM of second inner pre-maxillary tooth, occlusal view, from Kanapoi; labial sideat top, lingual at bottom

S. lothagamensis, and Kanapoi may have provideda more favourable environment for them.

Sindacharax mutetii Stewart, 2003(Figures 14–17)

EMENDED DIAGNOSIS. Second inner premax-illary tooth distinguished from Sindacharax leper-sonnei Greenwood and Howes, 1975 and S. loth-agamensis by cusps forming ridges rather than dis-crete cusps as in S. lepersonnei and S. lothagamen-sis. Distinguished from S. deserti Greenwood andHowes, 1975, by absence of raised circular ridgeradiating from the dominant lingual cusp; distin-guished from S. greenwoodi Stewart, 1997, by lackof the ridged arc surrounding dominant lingualcusp, and distinguished from all other Sindacharaxby broad oval shape.

HOLOTYPE. A second inner premaxillarytooth, collected from Lothagam by Sam N. Mutetiand Peter Kiptalam in 1993 from Site 1944 in theApak Member of the Nachukui Formation, andnow housed in the collections of the National Mu-seums of Kenya, Nairobi, with the accession num-ber KNM-LT 38265.


Figure 17 Sindacharax mutetii, SEM of in situ second and third inner premaxillary teeth, occlusal view, from Kanapoi;labial side at top, lingual at bottom, medial to the right, lateral to the left

KANAPOI MATERIAL. 3156, 3 second innerpremaxillary teeth; 3845, 21 first inner premaxil-lary teeth, 26 second inner premaxillary teeth;3846, 14 first inner premaxillary teeth, 39 secondinner premaxillary teeth; 3847, 51 first inner pre-maxillary teeth, 75 second inner premaxillary teeth;3848, 43 first inner premaxillary teeth, 67 secondinner premaxillary teeth; 3849, 50 first inner pre-maxillary teeth, 73 second inner premaxillary teeth;ngui site, 28 first inner premaxillary teeth, 65 sec-ond inner premaxillary teeth.

Most first and second inner premaxillary teethrecovered were identical to those recovered fromthe Apak and Kaiyumung Members at Lothagam(Stewart, 2003) (Figs. 14, 15); however, a few sec-ond inner premaxillary teeth showed a slight devi-ation in cusp pattern (Fig. 16). Instead of the firstridge, which is anterior to the dominant cusp, tra-versing the whole width of the tooth, in some teethit was shortened and often bracketed by one orboth ends of the ridge anterior to it.

The large number of S. mutetii teeth recovered atKanapoi reflect a range of individual variations intheir cusp patterns. Several of the second and thirdinner premaxillary teeth recovered have similar pat-terns to their counterparts in situ on the premaxillarecovered from the Apak Member at Lothagam,which was ascribed to cf. S. mutetii (Stewart,2003). Therefore, the Lothagam premaxilla is nowincluded in S. mutetii (Fig. 17). This premaxilla re-

mains the only jaw element recovered which is as-cribed to S. mutetii.

A total of 555 teeth ascribed to S. mutetii wererecovered at Kanapoi, making it the most abundantof the Sindacharax species at that site. Sindacharaxmutetii teeth were also the most common teeth re-covered from the Apak Member deposits at Loth-agam, although this species was not recovered fromthe Murongori Member.

Stewart (2003) stated that S. mutetii was the onlySindacharax found at Kanapoi. However, furtherstudy of the Kanapoi specimens showed that, whileS. mutetii is by far the most common species re-covered, teeth of both S. lothagamensis and S. how-esi Stewart, 2003, are also present.

Sindacharax howesi Stewart, 2003

KANAPOI MATERIAL. 3845, 3 first inner pre-maxillary teeth; 3846, 1 first inner premaxillarytooth; 3847, 8 first inner premaxillary teeth; 3848,7 first inner premaxillary teeth, 2 second inner pre-maxillary teeth; 29287, 1 second inner premaxil-lary tooth.

Sindacharax howesi teeth were not common atKanapoi. Mainly first inner premaxillary teeth wererecovered, and these were identical to those foundin the northern Kaiyumung deposits at Lothagam.

Sindacharax howesi teeth were exclusively foundin the north Kaiyumung deposits at Lothagam,where they are numerous. Their appearance in the

Stewart: Fish m 31

Figure 18 Sindacharax sp., SEM of in situ third inner pre-maxillary tooth, from Kanapoi; labial side at top, lingualat bottom

Figure 19 Sindacharax sp., SEM of in situ fourth innerpremaxillary tooth, from Kanapoi; labial side probably tothe right, lingual probably to the left

Kanapoi deposits indicates a slightly earlier pres-ence (ca. 4.0 Ma) in the Turkana Basin than pre-viously thought.

Sindacharax sp.(Figures 18, 19)

As discussed above, outer premaxillary and dentaryteeth are indistinguishable between the species, andtherefore are referred as Sindacharax sp. Similarly,third and fourth inner premaxillary teeth are simi-lar among the species, and again were referred toSindacharax sp.

Third and Fourth Inner Premaxillary Teeth

KANAPOI MATERIAL. 3845, 16 third orfourth inner premaxillary teeth; 3846, 11 third orfourth inner premaxillary teeth; 3847, 43 third in-ner premaxillary teeth, 15 fourth inner premaxil-lary teeth; 3848, 25 third or fourth inner premax-illary teeth; 3849, 32 third or fourth inner premax-illary teeth; 29287, 12 third or fourth inner pre-maxillary teeth.

No third or fourth inner premaxillary teeth couldbe assigned to species, as they were very similarthroughout the deposits. Often the third and fourthteeth could not be distinguished from each other,as the only confirmed fourth premaxillary tooth(preserved in situ on the S. greenwoodi type speci-

men) is very worn and the cusp pattern almost in-distinguishable. However, based on comparisonwith the S. greenwoodi premaxilla and modernAlestes and Brycinus premaxillae, I have tentativelyassigned some teeth as third inner teeth (Fig. 18)and fourth inner teeth (Fig. 19).

Outer Teeth

While outer teeth are difficult to distinguish be-tween species, there are several distinct types. Sim-ilar to the Lothagam outer teeth (Stewart, 2003a),I have classified the Kanapoi teeth into types, withan indication to which species they are most con-sisistently associated.

Outer Premaxillary Teeth, Type A

KANAPOI MATERIAL. 3156, 4 outer premax-illary teeth; 3845, 26 outer premaxillary teeth;3846, 10 outer premaxillary teeth; 3847, 86 pre-maxillary outer teeth; 3848, 48 premaxillary outerteeth; 3849, 22 premaxillary outer teeth; 29287, 19premaxillary outer teeth.

Type A teeth consist of one dominant and twomuch smaller flanking cusps, which slope into ashort, uncusped platform on one side but have asteep shelf on the other side (see figs. 3.26 and 3.27


in Stewart, 2003). They have a round or oval at-tachment base. At Kanapoi, Type A teeth are as-sociated with both S. lothagamensis and S. mutetiiteeth; when associated with S. mutetii, they oftenhave elongated attachment bases.

Outer Premaxillary Teeth, Type B

KANAPOI MATERIAL. 3845, 5 outer premax-illary teeth; 3846, 2 outer premaxillary teeth; 3847,11 outer premaxillary teeth; 3848, 11 outer pre-maxillary teeth; 3849, 3 outer premaxillary teeth;29287, 1 outer premaxillary tooth.

Type B teeth are similar to Type A but have oneor more discrete cusps at the base of the platform(Stewart, 2003: figs. 3.26, 3.27). Their attachmentbase is round or a roundish oval. These teeth weremost common in sites where S. howesi was alsofound.

Outer Premaxillary Teeth, Type C

KANAPOI MATERIAL. 3848, 5 outer premax-illary teeth.

Type C teeth have a dominant central cusp,flanked by concentric or semiconcentric rows ofsmall cusps (Stewart, 1997: figs. 2, 3). Their at-tachment base is an elongated oval. These teethwere rare at Kanapoi, and no particular affiliationcan be ascertained.

Outer Dentary Teeth

The outer dentary teeth recovered were mainly first,second, and third teeth; fourth teeth are muchsmaller and fewer have been recovered. The firsttooth is usually truncated posteriorly, to accom-modate the inner tooth. There is considerable wearvisible on most dentary teeth, and it is often diffi-cult to describe any morphology on the teeth. Aswith premaxillary outer teeth, outer dentary teethcan be divided into types, although only Type Awas recovered at Kanapoi.

Outer Dentary Teeth, Type A

KANAPOI MATERIAL. 3156, 5 outer dentaryteeth; 3845, 85 outer dentary teeth; 3846, 61 outerdentary teeth; 3847, 205 outer dentary teeth; 3848,134 outer dentary teeth; 3849, 295 outer dentaryteeth; 29287, 122 outer dentary teeth.

All dentary teeth recovered at Kanapoi belongedto Type A, although many were too worn to ascer-tain type. These teeth have a dominant, pointedcusp and are flanked by two smaller cusps, whichform a shelf on one side, more elongated and lesssteep than that of the premaxillary teeth (illustratedin Stewart, 2003). On the other side, the cuspsslope into a broad platform, which is usually un-cusped but may be weakly cusped. The attachmentbase is much more elongated than in most premax-illary teeth. Outer dentary teeth were by far themost abundant of all Sindacharax teeth, probablybecause of their size and robust attachment bases.

Inner Dentary Teeth

KANAPOI MATERIAL. 3845, 8 inner dentaryteeth; 3846, 4 inner dentary teeth; 3847, 22 innerdentary teeth; 3848, 7 inner dentary teeth; 3849, 5inner dentary teeth; 29287, 5 inner dentary teeth.

These teeth are very similar in both Alestes andSindacharax. There is only one inner tooth on eachdentary in living individuals, and it is positionedposterior to a notch in the first outer dentary tooth.Inner dentary teeth are small and round in shape,with a single elongated centrally placed cusp.

Worn and/or Fragmented Teeth, Unassigned toPosition

KANAPOI MATERIAL. 3156, 1 tooth; 3845, 6teeth; 3846, 48 teeth; 3847, 85 teeth; 3848, 50teeth; 3849, 4 teeth; 29287, 50 teeth.

Order Siluriformes

Family Bagridae or Family Claroteidae

KANAPOI MATERIAL. 3156, 1 pectoral spinefragment; 3847, 1 cranial spine.

These catfish elements are referred to the familylevel both because of their incomplete nature andthe similarity of these elements between some bag-rid and claroteid species. They represent small in-dividuals, probably no longer than 50 cm in totallength.

Bagrid and/or claroteid catfish elements werecommon in the field at Kanapoi, often representinglarge individuals (approximately 1 m in length).Most of these elements were not collected. Manyof these appeared to belong to Clarotes Kner, 1855,a large catfish which today often inhabits deltaicregions. Bagrids and claroteids, particularly BagrusBosc, 1816, and Clarotes, are known from theMio–Pliocene deposits at Lothagam (Stewart,2003) and at Koobi Fora (Schwartz, 1983), as wellas other Cenozoic deposits in Africa. They do notappear to have radiated in the Turkana Basin asthey did in the Western Rift (Stewart, 2001), al-though they are more common in the Plio–Pleisto-cene deposits at eastern Turkana.

Family Clariidae

Clarias Scopoli, 1777

Heterobranchus Geoffroy Saint-Hilaire, 1809

Clarias sp. or Heterobranchus sp.

KANAPOI MATERIAL. 3847, 2 caudal verte-brae; 3849, 2 trunk vertebrae, 1 caudal vertebrae.

These vertebrae are referred to Clarias or Het-erobranchus because of great similarity between theelements. These vertebrae derive from small indi-viduals (,50 cm total length).

Clariid elements were abundant at Kanapoi, butnot collected. As with the bagrid catfish, many el-ements appeared to come from large individuals, upto 2 m in length. Clarias is a bottom-dwelling, in-

Stewart: Fish m 33

Figure 20 Synodontis sp., SEM of dentary tooth, fromKanapoi; side view

shore fish, which can tolerate highly deoxygenatedwaters. Clariid remains were common throughoutthe Lothagam deposits (Stewart, 2003) and in lateCenozoic deposits of Africa (Stewart, 2001). Ten-tative identifications are reported in the mid-Mio-cene from Bled ed Douarah, Tunisia (Greenwood,1973), and Ngorora, Kenya (Schwartz, 1983). Def-inite clariid remains are known from Miocene de-posits in Sinda, Congo (Van Neer, 1992), and Chal-ouf, Egypt (Priem, 1914); Mio–Pliocene deposits inManonga, Tanzania (Stewart, 1997); Mio–Pleisto-cene deposits in the Western Rift (Van Neer, 1994);Pliocene deposits in Wadi Natrun, Egypt (Green-wood, 1972); and Plio–Pleistocene deposits at Koo-bi Fora (Schwartz, 1983). Extant Clarias is repre-sented by C. lazera Cuvier and Valenciennes, 1840,in Lake Turkana. Clarias is widespread throughoutAfrica, including the Nile, Congo, and Zambezi Ba-sins.

Heterobranchus has a similar appearance andsize to Clarias, but may be more sensitive to highsalinity values. Modern H. longifilis Valenciennes,1840, is present in Lake Turkana, but is rare. LikeClarias, Heterobranchus is widespread throughoutthe major river basins of Africa. It was identified inlate Pleistocene Lake Edward Basin (Congo) depos-its (Greenwood, 1959).

Family MochokidaeSynodontis Cuvier, 1817

Synodontis sp.(Figures 20, 21)

KANAPOI MATERIAL. 3845, 5 teeth; 3847, 1cranial spine base.

Synodontis teeth were not common in the Kan-apoi sites sampled, suggesting Synodontis was nota dominant presence at Kanapoi. The teeth are lo-cated on the dentary and are curved (Fig. 20). Theyaveraged about 1 mm in width, similar to modernSynodontis in Lake Turkana, suggesting the fossilfish reached 30–35 cm in total length (and muchlarger than the other Lake Turkana mochokid,Mochocus de Joannis, 1935, which reaches only6.5 cm in length). The cranial spine base recoveredis fragmentary (Fig. 21) but very similar to that ofmodern Synodontis. In life, it is positioned anteriorto the dorsal cranial spine and resembles a trun-cation of the spine.

Synodontis was probably not common at Kana-poi, as its remains normally preserve well. It wasalso not common at Lothagam, although consis-tently present through the deposits. Synodontis in-habits all zones of lakes and rivers, and is omniv-orous, eating insects, small fish, mollusks, and zoo-plankton. Fossil Synodontis is also known fromMiocene deposits at Rusinga and Chianda, Kenya(Greenwood, 1951; Van Couvering, 1977), Mog-hara and Chalouf, Egypt (Priem, 1920), and Bleded Douarah, Tunisia (Greenwood, 1973); Mio–Pleistocene deposits in the Western Rift (Green-wood and Howes, 1975; Van Neer, 1992, 1994);Pliocene deposits in the Western Rift (Stewart,1990) and Wadi Natrun (Greenwood, 1972); andPlio–Pleistocene deposits at Koobi Fora (Schwartz,1983). Two species of Synodontis inhabit modernLake Turkana—S. schall Bloch and Schneider,1801, and S. frontosus Vaillant, 1895. Synodontisis also widespread in systems throughout the Afri-can continent.

Order Perciformes

Suborder Percoidei

Family Latidae

Lates Cuvier, inCuvier and Valenciennes, 1828

Lates niloticus (Linnaeus, 1758)

KANAPOI MATERIAL. 3845, 1 hyomandibu-lar, 1 premaxilla, 1 dentary, 1 first trunk vertebra,2 trunk vertebrae, 1 caudal vertebra; 3847, 2 pre-maxillae, 2 posttemporal, 1 quadrate, 1 articular, 1basioccipital fragment, 1 vomer, 6 first trunk ver-tebra, 1 trunk vertebra; 3848, 1 basioccipital, 1premaxilla, 1 vomer.

These elements are identical to those in modernLates niloticus and represent fish of a diverse sizerange. Several large fossil elements were comparedwith modern L. niloticus elements recovered fromthe lake margin, and these indicated that many ofthe Kanapoi fish had an estimated total length ofover 2 m.

Many elements of Lates niloticus were observedin the field at Kanapoi, but only those listed abovewere collected, for their diagnostic value. Many of


Figure 21 Synodontis sp., SEM of cranial spine base, fromKanapoi, ventral view

the bones represented large individuals, estimatedto be approximately 2 m in length. Clearly, L. nil-oticus was a common component of the Kanapoifish fauna, and with many large individuals musthave been one of the most voracious consumers offish in the aquatic food chain. Modern Lates in-habits most zones of lakes and rivers, although itonly tolerates well-oxygenated waters. It is highlypiscivorous.

Elements of fossil Lates spp. are common in Af-rican deposits (Stewart, 2001) and are known fromMiocene deposits from Rusinga, Kenya (Green-wood, 1951), Gebel Zelten and Cyrenaica, Libya,(Arambourg and Magnier, 1961), Moghara andChalouf, Egypt (Priem, 1920), Bled ed Douarah,Tunisia (Greenwood, 1973); Mio–Pliocene depositsat Lothagam, Kenya (Stewart, 2003); Plio–Pleisto-cene deposits from Lakes Albert and Edward Basins(together with Semlikiichthys rhachirhinchus)(Greenwood, 1959; Greenwood and Howes, 1975;Stewart, 1990; Van Neer, 1994); an unpublishedreport from Marsabit Road, Kenya (in Schwartz,1983), the lower Omo Valley (Arambourg, 1947),and Koobi Fora (Schwartz, 1983); and Pliocene de-posits from Manonga, Tanzania (Stewart, 1997),and Wadi Natrun, Egypt (Greenwood, 1972). Latesniloticus has also been reported from Messinian(late Miocene) deposits in Italy, the only confirmedreport of this species in Europe (Otero and Sorbini,1999). Elements formerly identified as Lates fromEocene deposits in Fayum, Egypt (Weiler, 1929),

were referred to Weilerichthys fajumensis (Oteroand Gayet, 1999b). Modern Lates is known fromLake Turkana (L. niloticus and L. longispinis Wor-thington, 1932) and is widespread throughoutnorthern, eastern, and western Africa from Senegalto and including the Nile and Congo River Basins.

Percoidei incertae sedis

Semlikiichthys Otero and Gayet, 1999

Semlikiichthys rhachirhinchus(Greenwood and Howes, 1975)

Semlikiichthys cf. S. rhachirhinchus

KANAPOI MATERIAL. 3845, 4 first trunk ver-tebrae, 16 trunk vertebrae, 2 caudal vertebrae;3846, 1 dentary, 1 first trunk vertebra, 5 trunk ver-tebrae, 4 caudal vertebrae; 3847, 4 dentaries, 1 firsttrunk vertebra, 9 trunk vertebrae, 3 caudal verte-brae; 3848, 1 vomer, 2 basioccipital, 4 first trunkvertebrae.

All material collected at Kanapoi is identical todrawings of Semlikiichthys rhachirhinchus (former-ly Lates rhachirhinchus [Greenwood and Howes1975] but renamed S. rhachirhynchus [Otero andGayet, 1999a]; this author adheres to the originalspelling [Greenwood and Howes, 1975] for ‘‘rhach-irhinchus’’), and is also identical to material col-lected at Lothagam, figured and described as Sem-likiichthys cf. S. rhachirhinchus (Stewart, 2003).Full descriptions and photos of the extensive Sem-likiichthys cf. S. rhachirhinchus material fromLothagam are found in the Lothagam volume(Stewart, 2003), where it is compared with the orig-inal drawings of L. rhachirhinchus (Greenwoodand Howes, 1975).

In particular, the vomer recovered from Kanapoiis fully described in the Lothagam volume (Stewart,2003), as it is the only vomer recovered from eitherKanapoi or Lothagam which is almost identical tothe type S. rhachirhinchus vomer (Greenwood andHowes, 1975), and is important in the naming ofthese fossils (rhachirhinchus means loosely ‘‘snoutwith spine’’).

The Kanapoi elements establish a strong presenceof Semlikiichthys cf. S. rhachirhinchus at Kanapoi.

As at Lothagam, Lates niloticus and Semliki-ichthys cf. S. rhachirhinchus appear to have coex-isted at Kanapoi. Both groups of fish seem to haveattained large size, up to 2 m in length. This authorhas previously suggested (Stewart, 2001, 2003) thatthe presence of Semlikiichthys in the Turkana Basinresulted from exchange of faunas with the LakesAlbert and Edward Basins, the only other basins inwhich Semlikiichthys is known. Its reasonably com-mon presence in Kanapoi further supports the sug-gestion of exchange. The identification of a palatinein Wadi Natrun Pliocene deposits probably refer-able to Semlikiichthys (Greenwood, 1972; Green-wood and Howes, 1975; discussed in Stewart 2001,2003) also supports a more widespread faunal ex-

Stewart: Fish m 35

change within the Nile-linked systems, extending tothe Egyptian Nile area.

Lates or Semlikiichthys

KANAPOI MATERIAL. 3156, 3 first trunk ver-tebrae, 1 caudal vertebra; 3845, 1 dorsal spine;3846, 1 trunk vertebra; 3847, 1 maxilla fragment,1 basioccipital, 1 pelvic spine; 3848, 1 basioccipitalfragment, 4 vertebra fragments.

Perciformes IndeterminateKANAPOI MATERIAL. 3156, 5 pelvic spines.Pelvic spines are often difficult to distinguish be-

tween cichlids and Lates/Semlikiichthys. One pelvicspine appears to be more similar to those of cich-lids, but not enough for positive identification. Ifso, it would be the only cichlid fossil recovered atKanapoi. Cichlids are similarly rare at Lothagam.

PALEOECOLOGY

The Kanapoi fish fauna is characterized by two tro-phic components: large, piscivorous fish, in partic-ular the polypterids, Gymnarchus, Hydrocynus,Lates (and probably Semlikiichthys by analogy),and the bagrid and clariid catfish; and medium tolarge molluscivores, including Hyperopisus, Gym-narchus (which is also a piscivore), Sindacharax,and possibly Labeo. Together with the numerouselements of the crocodile Euthecodon Fourteau,1920, identified in the Kanapoi deposits, there wasclearly much piscivory in this region of the Lon-yumun lake (see, e.g., Tchernov, 1986, for detailsof Euthecodon). While Euthecodon’s diet probablyconsisted of the plethora of fish in the lake, the dietof the piscivorous fish must have included the nu-merous Sindacharax, Hyperopisus, and Labeo in-dividuals, as well as smaller fish whose elementswere not preserved. The near-absence of herbivo-rous fish, including Barbus, Alestes, and the largetilapiine cichlids is surprising. Most of these groupsare common in modern Lake Turkana and the Nilesystem, and would be expected in the Pliocene lake.Certain absences may be explained by unfavorableenvironmental conditions (see DISCUSSION ANDSUMMARY section). Barbus and the large tilapiinecichlids are generally scarce in African fossil de-posits prior to the Pleistocene (Stewart, 2001).

The diversity and composition of taxa represent-ed at Kanapoi is reminiscent of the modern OmoRiver Delta in northern Lake Turkana, which is in-habited, among other fish, by mormyriforms, char-acoids, bagrids, claroteids, and percoids. Gymnar-chus and Clarotes in particular prefer delta regions(Lowe-McConnell, 1987). Many of the fish in themodern Omo River Delta region are intolerant ofsaline waters and therefore inhabit the delta and thelower reaches of the Omo River because they can-not tolerate the more saline Lake Turkana waters.Modern Lates is intolerant of deoxygenated waters,and the modern mormyriforms are intolerant of sa-line waters. By analogy with the modern Omo Riv-

er Delta, Kanapoi waters may also therefore havebeen well-oxygenated and fresh.

The scarcity of fish such as Protopterus, Polyp-terus Saint-Hilaire, 1802, and Heterotis Ruppell,1829, which were relatively common in the Na-wata Formation at Lothagam, may signify an ab-sence of vegetated, shallow backwaters or bays, asthese are the type of habitats frequented by modernmembers of these taxa. The nearby Pliocene site ofEshoa Kakurongori contained numerous Protopte-rus toothplates, indicating a very different environ-ment from Kanapoi.

DISCUSSION AND SUMMARY

Because the Kanapoi fish fauna comes primarilyfrom one phase in the Kanapoi Formation—the la-custrine phase—there are no evolutionary or envi-ronmental transitions documented as was apparentthrough the Nawata and Nachukui Formations atthe nearby Lothagam site. Nevertheless, the faunaalters some of the evolutionary and biogeographicinterpretations made from the Lothagam fauna, asdiscussed below.

Most surprising is the comparison of the taxo-nomic composition from the Lothagam Muruon-gori deposits, Kanapoi deposits, and what the au-thor has observed from the Ekora site deposits, allof which are presumed to derive from the Lonyu-mun Lake. The Muruongori deposits contain sim-ilar taxa to that at Kanapoi (Table 1), but also in-clude two Sindacharax taxa—S. deserti and S.greenwoodi—and two Tetraodon Linnaeus, 1758,taxa—T. fahaka Hasselquist, 1757, and Tetraodonsp. nov., Stewart, 2003—which are common atMuruongori and at Ekora but which are completelyabsent from Kanapoi. Further, the most commonSindacharax species at Kanapoi—S. mutetii—is ab-sent in the Muruongori Member and apparently inthe Ekora fauna, although common in the ApakMember of Lothagam.

There are several possible explanations for thisdisparity in taxa between Kanapoi on one hand andMuruongori and Ekora on the other, which derivefrom the same lake. First, the different sites mayrepresent different time intervals in the lake’s his-tory: the Ekora tetrapod fauna is said to be youngerthan that at Kanapoi (Maglio in Behrensmeyer,1976), and the Muruongori Member may also beslightly younger than at Kanapoi. The ‘‘new’’ Sin-dacharax and Tetraodon taxa from Muruongoriand Ekora may represent immigrants from a newinflow which was not present during Kanapoi de-position. The abundance of S. mutetii at both Kan-apoi and in the Apak Member of Lothagam, whichdates earlier than Muruongori and Ekora, may sug-gest an earlier deposition of the Kanapoi deposits,and a faunistic change between the Kanapoi, andMuruongori and Ekora waters. Sindacharax mu-tetii is completely absent from Muruongori andEkora.

Alternatively, the Kanapoi and Muruongori and


Table 1 Fish taxa found in Mio–Pliocene deposits in Nawata, Apak, Muruongori, and Kaiyumung Members, Lothagam(Stewart, 2003) and Kanapoi (this report); see Feibel (2003a) and McDougall and Feibel (1999) for detailed informationabout the geochronology, geological formations, and members at Lothagam

Nawata Apak Muruongori Kaiyumung Kanapoi

Protopterus sp.Polypterus sp.Heterotis sp.Hyperopisus sp.Gymnarchus sp.

111

1

11111

1111

11

11

1

11

Labeo sp.Barbus sp.Distichodus sp.Hydrocynus sp.Brycinus macrolepidotus

?1

11

1111

1

1

11

1

11111

Alestidae sp.Sindacharax lothagamensisS. mutetiiS. howesiS. deserti

11 1

1

1

1

111

111

S. greenwoodiSindacharax sp.Bagrus sp.Aff. Bagrus sp.Clarotes sp.

1

11

1

11

11

11111

1

Bagridae/ClaroteidaeSchilbe sp.Clarias or HeterobranchusSynodontis sp.Lates niloticus

1111

111

1111

1

111

Lates sp.Semlikiichthyscf. S. rhachirhinchusCichlidaeTetraodon sp. nov.Tetraodon sp.

1

1

1

1

1

1111

1

11

1

1

1

Ekora deposits may represent different ecologicalzones in the Lonyumun Lake, with the ‘‘new’’ taxarestricted ecologically to local habitats and/or ba-sins. Again the analogue of the modern Omo RiverDelta is appropriate here, with many taxa restrictedto the delta region and not occurring in Lake Tur-kana proper.

A third alternative is that the field sampling wasnot extensive enough, and elements of the ‘‘new’’taxa were not recovered at Kanapoi. This alterna-tive seems less likely, as extensive screening was un-dertaken at all areas, and teeth of the ‘‘new’’ taxashould at least be somewhat represented at Kana-poi. Further, the Tetraodon toothplates are very ro-bust and distinctive as fossils, and extensive survey-ing at Kanapoi should have recovered at least sometoothplates, if this taxon had been present.

A third ‘‘new’’ taxon—cf. Semlikiichthys rhach-irhinchus—was rare in earlier Lothagam deposits,but was common in the Muruongori Member atLothagam, at Kanapoi, and at Ekora. This percoidapparently coexisted with Lates niloticus, whichwas also recovered in large numbers. Stewart

(2001) has reported that S. rhachirhinchus elementswere also found in the Western Rift and probablyat Wadi Natrun, suggesting interchange betweenthe three systems. Otero and Sorbini (1999) havesuggested that the genus Lates diversified in thefresh waters of Europe and Africa in the Miocene,from a Mediterranean origin. Further work is need-ed to clarify the relationships of S. rhachirhinchus.

In sum, the Kanapoi fauna is of considerable in-terest for several reasons. It has an unusual com-position of mainly large piscivorous fish and me-dium to large molluscivores, and a scarcity of her-bivorous fish. This composition is considerably dif-ferent from that of modern Lake Turkana, which ismuch more evenly balanced between herbivoresand piscivores. The scarcity of herbivores such asBarbus and the large tilapiine cichlids, common inthe modern lake and the Nile River system, is par-ticularly enigmatic.

While the Kanapoi fauna shares many taxa withthe similarly aged Muruongori Member fauna fromLothagam and also from Ekora, it also shows somedifferences. The dominance of Sindacharax mutetii

Stewart: Fish m 37

at Kanapoi and in the Apak Member at Lothagamcontrasts with its absence in the Muruongori de-posits and at Ekora, as does the dominance of S.deserti and Tetraodon at Muruongori and Ekora,and their absence from Kanapoi and the ApakMember. Whether these disparities reflect ecologi-cal variants or chronological differences needs tobe further studied.

ACKNOWLEDGMENTS

I express my gratitude to Dr. Meave Leakey, who invitedme to study the fossil fish from Kanapoi and providedsupport in the field. My gratitude also to Sam N. Muteti,who worked extremely hard with me in the field and pro-vided additional help at the National Museums of Kenya.Thanks also to the members of the National Museums ofKenya fossil team for their help in collecting fossils. Spe-cial thanks to Kamoya Kimeu for leadership and supportin the field, and to the Paleontology staff at the NationalMuseum in Nairobi for assistance in the lab. Specialthanks to Donna Naughton for scanning electron micro-scopic photography. My thanks to the Canadian Museumof Nature Research Advisory Council for transport andfield assistance. Many thanks as well to John Harris foreditorial assistance with the manuscript, to Frank Brownfor discussions in Kenya on the fish and geology, to CraigFeibel for information on the sedimentary sequence, andto O. Otero, A. Murray, and P. Forey for helpful com-ments on the article.

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. 1999b. Weilerichthys fajumensis (Percoidei incer-tae sedis), new name and systematic position for La-tes fajumensis Weiler, 1929, from the Eocene of the


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. 2001. Palaeoichthyofaunas from the Lower Oli-gocene and Miocene of the Arabian Plate: Palaeoe-cological and palaeobiogeographical implications.Palaeogeography, Palaeoclimatology, Palaeoecology165:141–169.

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. 1920. Poissons fossiles du Miocene de l’Egypte.In Contribution a l’Etude des Vertebres miocenes del’Egypte, ed. R. Fourtau, 12-15. Cairo: GovernmentPress.

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. 1997. A new species of Sindacharax (Teleostei:Characidae) from Lothagam, Kenya, and some im-plications for the genus. Journal of Vertebrate Pale-ontology 17(1):34–38.

. 2001. The freshwater fish of Neogene Africa(Miocene–Pleistocene): Systematics and biogeogra-phy. Fish and Fisheries 2:177–230.

. 2003. Fossil fish remains from Mio–Pliocene de-posits at Lothagam, Kenya. In Lothagam: Dawn ofhumanity in Eastern Africa, eds. M. G. Leakey andJ. M. Harris, 75–115. New York: Columbia Univer-sity Press.

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. 1994. Cenozoic fish fossils from the Albertine RiftValley in Uganda. In Geology and palaeobiology ofthe Albertine Rift Valley, Uganda–Congo. Vol. II:Palaeobiology, eds. M. Pickford and B. Senut, 89–127. Orleans: CIFEG Occasional Publications.

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EARLY PLIOCENE TETRAPOD REMAINS FROM KANAPOI,LAKE TURKANA BASIN, KENYA

JOHN M. HARRIS,1 MEAVE G. LEAKEY,2 AND

THURE E. CERLING3

APPENDIX BY ALISA J. WINKLER4

ABSTRACT. Kanapoi, located in the southwestern portion of the Lake Turkana Basin, is the type localityof the oldest East African australopithecine species, Australopithecus anamensis, and has yielded a diversetetrapod assemblage that includes more than 50 species. The terrestrial fossils derive from fluviatile sandsthat date between 4.17 and 4.07 Ma and which sandwich a lacustrine interval that represents the extensiveLonyumun Lake—a predecessor of Lake Turkana. The tetrapod assemblage is broadly similar to compa-rably aged assemblages from the nearby locality of Lothagam and the slightly older site of Aramis inEthiopia. Soil horizons from the succession suggest a mixture of habitats similar to those in the vicinity ofthe Omo Delta at the north end of the modern Lake Turkana. The Kanapoi biota, however, appears torepresent a mixture of open and closed xeric habitats.

INTRODUCTION

The early Pliocene locality of Kanapoi is located tothe southwest of Lake Turkana in northern Kenyaat 3683951.10E, 2818932.20N. The Kanapoi siteswere first collected in the mid-1960s (1965–67) byexpeditions from Harvard University under theleadership of Bryan Patterson. Significant amongthe 400 specimens collected by the Harvard Uni-versity parties are the holotypes of the elephantidLoxodonta adaurora Maglio, 1970, and rhinocer-otid Ceratotherium praecox Hooijer and Patterson,1972, two of the most characteristic components ofthe East African Pliocene biota, together with ahominid humerus that was tentatively identified asAustralopithecus sp. (Patterson et al., 1970). Someelements of the fauna were described in detail, in-cluding proboscideans (Maglio, 1970, 1973), suids(Cooke and Ewer, 1972), and rhinos (Hooijer andPatterson, 1972), but the remainder of the materialwas largely overlooked.

Kanapoi was subsequently recollected in the mid-1990s by National Museums of Kenya expeditionsunder the leadership of Meave Leakey. The verte-brate fauna was considerably augmented and thehominid hypodigm was expanded to include cra-nial, dental, and postcranial material of Australo-pithecus anamensis Leakey et al., 1995, currentlythe oldest recognized East African australopithecine

1. George C. Page Museum, 5801 Wilshire Boulevard,Los Angeles, California 90036, USA.

2. National Museums of Kenya, PO Box 40658, Nai-robi, Kenya.

3. Departments of Biology and Geology & Geophysics,University of Utah, Salt Lake City, Utah 84112, USA.

4. Shuler Museum of Paleontology, Southern Method-ist University, Dallas, Texas 75275, USA.

(Ward et al., 2001). The age of the Kanapoi biotais tightly constrained to between 4.17 and 4.07 Ma(Leakey et al., 1998) and, as such, it documents aperilacustrine assemblage from an interval of timethat is not well represented elsewhere in the LakeTurkana Basin.

We provide here a description of much of thefossil vertebrate material recovered by the HarvardUniversity and National Museums of Kenya expe-ditions. The fish and carnivorans are described sep-arately by Kathy Stewart and Lars Werdelin, re-spectively, in adjacent parts of this Contributions inScience issue, as is an assessment of the geologiccontext by Craig Feibel. The micromammals willbe investigated by Frederick Kyalo of the NationalMuseums of Kenya for his Ph.D. dissertation, buta preliminary assessment of this material by AlisaWinkler is appended to this contribution.

GEOLOGIC SETTING

The stratigraphic sequence at Kanapoi reflects de-position in fluviatile and lacustrine environmentsand has been studied by Denis Powers (1980) andCraig Feibel (2003b). A basal fluvial complex ofchannel sandstones and floodplain paleosols lies onthe dissected surface of Miocene volcanic rocks.Two devitrified tuffs in this lower fluviatile unithave yielded dates of 4.17 6 0.03 Ma (lower pu-miceous tuff) and 4.12 6 0.02 Ma (upper pumi-ceous tuff) (Leakey et al., 1995). In this unit, ver-tebrate fossils occur primarily in the vertic flood-plain paleosols. The basal complex is overlain byclaystones with ostracods and mollusks; these weredeposited within the early Pliocene LonyumunLake that extended throughout much of the LakeTurkana Basin. The vitric Kanapoi Tuff from theupper portion of the lower lacustrine sequence con-


tained pumices that were dated to 4.07 6 0.02 Ma(Leakey et al., 1998). This tuff cannot be matchedwith any tephra exposed in the northern part of theLake Turkana Basin but shows affinity with tephrafrom the Lake Baringo Basin. The lacustrine strataare overlain by extensive deltaic sandstones that arerich in vertebrate remains, and these are in turnoverlain by a second fluvial interval that has exten-sive conglomeratic channels near its top. The se-quence is capped by the Kalokwanya Basalt thathas been dated to 3.4 Ma, providing an upper limiton the age of the formation (Feibel, 2003b).

CONVENTIONS AND ABBREVIATIONS

The full accession number for Kanapoi specimenshoused at the National Museums of Kenya in Nai-robi begins with the prefix KNM-KP (e.g., KNM-KP 435). This prefix is abbreviated to KP in thedescriptive portions of the text and omitted alto-gether in the list of Kanapoi material at the begin-ning of each systematic section. The following ab-breviations appear in the lists of specimens and inthe tables:

ant 5 anteriorap 5 anteroposteriorBL 5 buccolingual

dist 5 distalEK 5 Ekora

frag 5 fragmenth/c 5 horn corejuv 5 juvenileKP 5 KanapoiLL 5 labiolingualLT 5 LothagamLt 5 leftlt 5 length

MD 5 mesiodistalmand 5 mandiblemax 5 maxillamet 5 width at metaloph(id)m/p 5 metapodialm/t 5 metatarsalPL 5 plastron length

post 5 posteriorprot 5 width at protoloph(id)prox 5 proximal

p/c 5 postcranialRt 5 righttr 5 transverse


Order Chelonia

Family Pelomedusidae

Turkanemys Wood, 2003

Turkanemys pattersoni Wood, 2003

KANAPOI MATERIAL. 435, carapace; 436,carapace; 437, carapace frags; 451, carapace frags;562, partial carapace and plastron; 30174, cara-

pace and plastron; 30438, carapace and plastron;30470, carapace and plastron; 30595, carapace;30597, carapace and plastron; 30618, carapaceand plastron.

Turkanemys pattersoni was recently describedfrom Lothagam (Wood, 2003). Its shell differs fromall other African pelomedusid species by virtue ofhaving trapezoidally shaped first vertebral scuteand in the tendency of the nuchal bone to be pro-portionally broader than in other species. The shelldiffers from all South American species of Podoc-nemis (to which many African fossil pelomedusidshave been referred in the past as a matter of con-venience) in having six rather than seven neuralbones and a triangular rather than pentagonal in-tergular with gulars meeting in the midline behindit. Turkanemys pattersoni also differs from all otherpelomedusid species in the structure of the cervicalseries, with articular surfaces being intermediate inshape between saddle joints of typical podocnemi-nes and procoelous condition of pelomedusines andErymnochelys madagascariensis Grandier, 1867.Turkanemys pattersoni is the most common che-lonian from Kanapoi.

Kenyemys Wood, 1983

Kenyemys sp. indet.

KANAPOI MATERIAL. 30419, carapace frags;30468, juvenile carapace and plastron.

Kenyemys williamsi Wood, 1983, differs from allother known pelomedusids by the following com-bination of characters: (a) a series of elongate tu-berosities forming an interrupted keel extendingalong the midline rearward from the dorsal surfaceof the second neural bone; (b) six neural bonesforming a continuous series, the anterior end of thefirst abutting directly against the rear margin of thenuchal bone and the sixth one being heptagonal;(c) outer corners of nuchal bone extending beyondlateral margins of first vertebral scute; (d) pentag-onal shape of first vertebral scute; (e) only eighthand posterior part of seventh pair of pleural bonesmeet at midline of carapace; (f) anterior plastrallobe truncated; (g) triangular intergular scute notoverlapping anterior end of entoplastron and onlypartially separating the gular scutes along the mid-line axis of the plastron (Wood, 1983). The occur-rence of two pelomedusid specimens with a midlinekeel on the carapace indicates the presence of an asyet undetermined species of Kenyemys.

Family Trionychidae

Tribe Cyclanorbini

Cyclanorbis Grey, 1854

Cyclanorbis turkanensis Meylan et al., 1990

KANAPOI MATERIAL. 17196, carapace miss-ing the eight pair of costals and the lateral portionsof all the left costals (holotype).

Only one specimen (the holotype) of this taxon

Harris, Leakey, Cerling, and Winkler: Tetrapods m 41

Figu

re1

KN

M-K

P10

552;

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is known from Kanapoi. The distinctly concave lat-eral margins of the carapace posterior to the fourthcostal together with the hypertrophied and distinct-ly V-shaped cross-section of the vertebrae centradistinguish this species from other species of Cy-clonorbis.

Cyclanorbini gen. and sp. indet.

KANAPOI MATERIAL. 17202, carapace.A relatively complete cyclanorbin carapace un-

fortunately lacks the diagnostic scutes that wouldpermit identification beyond the tribal level.

Trionychidae gen. and sp. indet.

KANAPOI MATERIAL. 30605, carapace andplastron frags.

This specimen comprises fragments of carapaceand plastron of a single individual that have thesculpted morphology characteristic of trionychidturtles but which cannot be identified beyond thefamily level.

Family Testudinidae

Geochelone Fitzinger, 1835

Geochelone crassa Andrews, 1914(Figure 1)

KANAPOI MATERIAL. 10552, complete shell;30199, carapace and plastron.

Geochelone is an almost cosmopolitan tortoisegenus in which the carapace and plastron are neverhinged and which often achieved large size. Geo-chelone crassa is a large (.700 mm PL) Africanform in which the pectorals are widest at the mid-line but narrow considerably on either side of themidline; gulars and pectorals fall short of the en-toplastron. This species is based on a partial plas-tron from the early Miocene locality of Karungu(Meylan and Auffenberg, 1986:281) but evidentlysurvived into the Pliocene. Meylan and Auffenberg(1986) identified KP 10552—a nearly complete butcrushed, meter-long shell of a large land tortoise—as G. crassa (Fig. 1) but erroneously documentedthe accession number as 10052. They noted thatmost of the shell was badly broken but sulci andbone sutures are visible on the ventral surface ofthe anterior lobe of the plastron. The pectorals arewidest at the midline (110 mm) but narrow later-ally (to 30 mm). The gular scutes appear to reachthe entoplastron but the pectorals do not.

cf. Geochelone sp. indet.

KANAPOI MATERIAL. 30439, carapace andplastron; 30614, half carapace and plastron.

Several specimens comparable in size to, orsmaller than, the extant leopard tortoise Geoche-lone pardalis Bell, 1828 were recovered from Kan-apoi by National Museums of Kenya expeditions.

Order Crocodylia

Family Crocodylidae

Crocodylus Laurenti, 1768

Crocodylus niloticus Laurenti, 1768(Figure 2)

KANAPOI MATERIAL. 18333, Lt. mand frag;18334, Lt. mand frag; 18336, incomplete skull;18337, young skull; 18338, adult skull; 30196, ar-ticulated skull and mand; 30437, skull frags;30492, cranial frags, scutes, and p/c frags; 30594,partial skull and mandible; 30604, skull.

The extant Nile crocodile is a moderate- to large-sized crocodylid with generalized rostrum of mod-erate proportion, median nasal promontorium, typ-ically 14 maxillary and 15 mandibular teeth andwith the anterior nuchal osteoderms well developed(Storrs, 2003). Ten relatively complete Crocodylusniloticus crania and/or mandibles were collected byNational Museums of Kenya expeditions (Fig. 2).Tchernov (1976, 1986) had reported that thebroad-snouted Rimasuchus lloydi (Fourteau, 1920)was the common crocodilian in the Lake TurkanaBasin and that C. niloticus had a very sparse recordin the Plio–Pleistocene. However, Storrs (2003)documented the presence of five crocodilian taxa,including both R. lloydi and C. niloticus at Loth-agam. Even so, it was somewhat surprising to findten C. niloticus cranial specimens in the Kanapoibiota but only one of R. lloydi. Nevertheless, theapparent dominance of the extant Nile crocodile inthe Kanapoi biota must be viewed with caution be-cause only the more complete crocodilian speci-mens were collected.

?Crocodylus sp. indet.(Figure 3)

KANAPOI MATERIAL. 30451, rostrum andsymphysis frags.

Associated rostrum and symphysis fragmentsdocument the presence of a second species ofbroad-nosed crocodile. This species can be distin-guished from broad-nosed crocodilians previouslydocumented from the Pliocene of East Africa by itsunusually long mandibular symphysis. R. lloydiand the extant species C. niloticus and C. cata-phractus Cuvier, 1824, all have short mandibularsymphyses whereas that of KP 30451 is more than10 cm long. This undetermined species is also char-acterized by the broad and straight anterior marginof the snout. No other fossil or extant crocodilianspecies is known to possess this combination of fea-tures (G. Storrs, personal communication).

Rimasuchus Storrs, 2003

Rimasuchus lloydi (Fourteau, 1920)(Figure 4)

KANAPOI MATERIAL. 30619, anterior ros-trum and mandible frags.


Figure 2 KNM-KP 18338; Crocodylus niloticus cranium, dorsal view; scale 5 5 cm


Figure 3 KNM-KP 30451; ?Crocodylus sp., cranium and mandible fragments; A 5 occlusal views of anterior rostrumand mandibular symphysis; B 5 dorsal view of anterior rostrum, ventral view of mandibular symphysis; scale 5 5 cm


Figure 4 KNM-KP 30619; Rimasuchus lloydi, anterior rostrum and mandible fragments, A 5 dorsal view; B 5 ventralview; C 5 lateral view; scales 5 10 cm


The genus Rimasuchus was proposed by Storrs(2003) for a very large, brevirostrine crocodylidthat had been previously referred to C. lloydi. Thespecies is characterized by premaxillae that arebroader than long and that had a relatively straightpremaxillae/maxillae palatal suture, a deep ‘‘ca-nine’’ occlusal notch, a slight dorsal maxillary boss,closely spaced anterior dentary teeth, broadly di-verging mandibular rami, and prominent dentaryfestoons. It is readily distinguished from C. niloti-cus by the lack of a nasal promontorium.

An anterior portion of a very large rostrum withassociated mandible was recovered from just belowthe Kanapoi Tuff. Measuring 326 mm across thewidest preserved portion of the anterior rostrum,the specimen represents the largest crocodylian in-dividual yet recovered from the Lake Turkana Ba-sin. The most distinctive features of R. lloydi, otherthan the absence of a nasal promontorium, are itsrelatively short but broad premaxillae and its shortand deep mandibular symphysis. The conformationof the Kanapoi specimen leaves no doubt that itrepresents R. lloydi.

Euthecodon Fourtau, 1920

Euthecodon brumpti (Joleaud, 1920)

KANAPOI MATERIAL. 18330, complete skulland mand; 18331, rostrum frag; 18332, articulatedskull and mand frag; 30653, mand symphysis;30176, edentulous mand; 30266, mand frags;30407, mand.

Euthecodon brumpti is a very large eusuchian inwhich the extremely elongate and narrow rostrumhas deeply scalloped dental margins. The premax-illae and nasals are attenuated but the narial ridgeis prominent. A moderate premaxillary/maxillarydiastema is located behind four premaxillary teeth.The skull table is small and nearly square, the oc-ciput vertical, the mandibular symphysis long, andthe teeth isodont and slender (Storrs, 2003).

Half a dozen specimens of slender-snouted croc-odilians were recovered by National Museums ofKenya expeditions. These clearly belong to E.brumpti, a species distinguished by its slender snoutand long slender curved teeth, rather than to thegavial reported by Storrs (2003) from the lowerNawata Formation at the nearby site of Lothagam.

Order Struthioniformes

Family Struthionidae

Struthio Linnaeus

Struthio sp. indet.

KANAPOI MATERIAL. 29300, eggshell frags;30221, eggshell frags; 30223, eggshell frags;30262, eggshell frags; 30490, eggshell frags;32522, eggshell frags; 36599, eggshell frags.

Several occurrences of fossil ostrich eggshell frag-ments were noted on the surface of the fossiliferousstrata at Kanapoi and several voucher specimens

were collected by National Museums of Kenya ex-peditions. These shell fragments all had the stru-thious pore pattern characteristic of living ostriches(Sauer, 1972) and the pore basins are of similar sizeand shape to those reported from the upper Na-wata at Lothagam (Harris and Leakey, 2003a). Thed13C content of the fossil eggshell is more negativethan those of extant ostriches from Kanapoi andthe d18O is more positive. It would appear thatthere was a greater proportion of C3 vegetation inthe Pliocene ostrich diet compared with that ofmodern ostriches on the west side of Lake Turkana.

Order Pelecaniformes

Family Anhingidae

Anhinga Brisson, 1760

Anhinga sp. indet.KANAPOI MATERIAL. 39325, Lt. humerus.This family is represented by the left humerus of

a darter of comparable size to the extant Africandarter.

Order Ciconiiformes

Family Ciconiidae

Mycteria Linnaeus

Mycteria sp. indet.KANAPOI MATERIAL. 30231, Lt. dist tibia,

prox Rt. tibiotarsus, Lt. radiale, and long bonefrags.

Storks were represented at Kanapoi by a singleassociation of long bone fragments.

Order Charadriiformes

Family Anatidae

Gen. and sp. indet.KANAPOI MATERIAL. 39326, proximal Lt.

humerus.The Anatidae was represented at Kanapoi by a

goose-sized left humerus fragment.

Order Primates

Family Galagidae

Galago Geoffroy, 1796The modern species range in size from the largestGalago crassicaudatus Geoffroy, 1812 (1,122–1,750 g) to the smallest, Galago demidovii (Fisher,1806) (69–81 g), and they inhabit a variety of hab-itats including primary and secondary lowland andmontane forests, gallery forests, Acacia woodlands,savannahs, thorn scrub, and forest edge.

cf. Galago sp. indet.(Figure 5)

KANAPOI MATERIAL. 30260 Rt. mand frag.(M2).


Figure 5 KNM-KP 30260; cf. Galago sp. indet., rightmandible fragment (M2), occlusal view; scale 5 5 mm

Mandibular fragment, KP 30260, is approxi-mately the size of Galago demidovii, the smallestliving galago. The specimen is too fragmentary toallow precise identification. Due to their small size,galagos are rare in the fossil record and little isknown of their distribution or evolution in the Pli-ocene.

Family Cercopithecidae

Subfamily Colobinae

Although rare elements in fossil assemblages, theColobinae were a diverse group in the Pliocene, atwhich time they appear to have undergone a majorradiation. Several species of large colobines areknown from Pliocene and early Pleistocene depositsin the Turkana Basin, the Baringo Basin, and fromOlduvai (Leakey, 1982, 1987). The postcranialmorphology indicates differing degrees of arboreal-ity but all appear to have been more terrestrial thanextant east African colobines. Fossil Colobinae in-clude at least three genera—Paracolobus Leakey,1969, Rhinocolobus Leakey, 1982, and Cercopithe-coides Mollet, 1947—and are known from severalrelatively complete skeletons. Smaller colobineswere also diverse but are less well represented byfossils. The genus Kuseracolobus Frost, 2001 hasbeen described from early Pliocene deposits at Ar-amis in the Awash Valley, Ethiopia, where colo-bines constitute an unusually high proportion(56%) of the cercopithecid assemblage. At Kana-poi, at least three species are represented, two mod-erately large but of indeterminate affinities, and theother an indeterminate species of Cercopithecoides.Such diversity at Kanapoi indicates that the colo-bine radiation began prior to 4.1 million years ago.

Cercopithecoides Mollet, 1947

Cercopithecoides is one of the best-represented co-lobine genera in the East African Pliocene and earlyPleistocene. Until recently, only two East Africanspecies were recognized, C. williamsi Mollet, 1947,and C. kimeui Leakey M. G., 1982, but additionaltaxa are now described from Lothagam (Leakey etal., 2003) and at Leadu in Ethiopia (Frost and Del-son, 2002). Features of the postcranial anatomy in-

dicate that Cercopithecoides was probably the mostterrestrial of the Pliocene colobines.

cf. Cercopithecoides sp. indet.(Figure 6; Tables 1, 2, 4)

KANAPOI MATERIAL. 29255, mandible (Rt.P3–M3, Lt. P3–M1); 31741, broken M1 or M2;32870, Lt. P4; 36967, Lt. M3; 37382, Rt. /C;43120, P3 talonid.

A handful of specimens represent a small speciesof colobine. The well-preserved mandible permitstentative taxonomic assignment to Cercopithecoi-des. The mandible probably represents a female: al-though the canines are lost, their alveoli are notlarge and the honing facet of the P3 is short. Thesymphysis is broken toward the alveolar margin,the right body extends behind the M3, and the leftbody terminates behind M1. The M1s are quiteheavily worn, the M2 and the premolars less so, andthe M3 has relatively light wear. Slight damage tothe body beneath the P3s on both sides may well befrom carnivore chewing.

The mandibular morphology is similar to that ofCercopithecoides with a relatively shallow andmoderately thick mandibular corpus. However, theanterior face of the symphysis lacks a median men-tal foramen and is more sloping and less flattenedthan in other known species. Below the deep genio-glossal pit, the inferior torus is well developed. Al-though the canines are missing and the alveoli dam-aged, the dental arcade appears to be narrower be-tween the canine alveoli. The inferior margin of themandibular body is clearly defined anteriorly wherethere is a distinct and deep digastric fossa thatmerges posteriorly with the submandibular fossa.The mylohyoid line is prominent, providing consid-erable strength to the body and defining the upperextent of the submandibular fossa. With the excep-tion of the less worn M3, the teeth are heavilyworn, as is so often the case with Cercopithecoides.

Colobinae gen. et sp. indet. A(Figure 7; Tables 1–3)

KANAPOI MATERIAL. 31736, skull frag andmale associated lower teeth (I, and Lt. P4, partialLt. and Rt. C, Rt. P3, and molar, and molar frag);29307, Rt. juv mand (dP4, I1–P4 in crypts); 30408,Lt. mand (erupting P3 and P4, M1–2); 30496, Lt. /C;32803, Rt. M1or2; 32525 male partial Lt. C/;32821, Lt. M2; 36830, Lt. mandible (M1, crypt forM2).

The specimens assigned to this taxon are frag-mentary, largely subadult, and mostly from thelower jaw. They represent a fairly large colobinethat has relatively large high-crowned premolars(compared with the size of the molars). The un-erupted P3 of KP 30408 has a large protoconid anddistinct metaconid as well as a large distal fovea.The remaining specimens are tentatively referred tothis taxon but could equally well belong to the fol-lowing taxon.


Figure 6 KNM-KP 29255; cf. Cercopithecoides sp. indet., mandible (Lt. P3–M1, Rt. P3–M3), A 5 occlusal view; B 5inferior view; C 5 right lateral view; D 5 anterior view; scale 5 3 cm

Table 1 Kanapoi Colobinae upper dentition measure-ments

cf. Cercopithecoides sp. indet.

M3

MD LL

36967 8 8.2

Colobinae gen. et sp. indet. A

C/

MD LL

32525 7.3 12.9

Colobinae gen. et sp. indet. B(Figure 8; Table 2)

KANAPOI MATERIAL. 29308, male Lt. mand(erupting P3, roots C, P4–M1).

This is a juvenile mandible with the P3 erupting.Although of similar size, the P3 differs significantlyfrom that of Colobinae gen. et sp. indet. A. It hasa large single cusp, the protoconid, and a small dis-tal fovea in contrast with the two cusps and largedistal fovea of KP 30408.

Subfamily Cercopithecinae

Tribe Papionini

The Papionini are the dominant cercopithecids inmost Pliocene and Pleistocene sites in East Africa.Parapapio Jones, 1937, was the common genus inthe early Pliocene, but was later replaced by Ther-opithecus Geoffroy, 1843. At Aramis, in the MiddleAwash, a new 4.4 million year old papionin, Plio-papio alemui Frost, 2001, has been recovered(Frost, 2001). Pliopapio Frost, 2001, is distin-guished from Parapapio by the presence of an an-teorbital drop, a distinct ophryonic groove, and ashorter and more rounded symphysial profile. Theabsence of an anteorbital drop is the sole diagnosticcharacter separating Parapapio from Papio Muller,1773.

Genus Parapapio Jones, 1937

Parapapio is recorded from almost all East AfricanPliocene sites, and is generally believed to have giv-en rise to Papio, from which it can be differentiatedonly by its facial profile. A number of species havebeen described and differ largely on the basis ofsize—a criterion that is not easy to apply when


Tab

le2

Kan

apoi

Col

obin

aelo

wer

dent

itio

nm

easu

rem

ents

Side

I 1

MD

LL

/C

MD

LLM

axhe

ight

P 3

MD

BL

Hei

ght

P 4

MD

BL

M1

MD

BL

M2

MD

BL

M3

MD

LL

cf.

Cer

copi

thec

oide

ssp

.in

det

2925

529

255

3174

132

870

3738

243

120

Fem

ale

Mal

e

L R R R6.

63.

4

5.8

,6.

54.

34 5.

8

5.9

6 6.3

5 4.8

4.7

7.1

7.1

5.8

5.9

8.7

7.9

6.7

10.2

6.4

Col

obin

aege

n.et

sp.

inde

t.A

3040

830

496

3173

632

803

3282

136

830

L R L L

45.

710

.710

.4e

7.9

5.1

16.4

16.6

9.1

611

.7.

0

6.3

.6.

0

5.1

9.5

8.5

6.7

6.1

9.6

9.8

7.5

7.6

Col

obin

aege

n.et

sp.

inde

t.B

2930

86.

84.

6.

12.3


Table 3 Kanapoi Colobinae gen. et sp. indet. A deciduousteeth

Lower dentition

dP4

MD BL

29307 6.6 4.7

Figure 7 KNM-KP 30408; Colobinae gen. et sp. indet. A,left mandible, occlusal view; scale 5 2 cm

Table 4 cf. Cercopithecoides sp. indet mandibular mea-surements

29255

Depth below P4/M1 junctionDepth below M2/M3 junction3Max thickness below M1

Max thickness below M3

Length tooth row P3–M3

20.921.410.410.939.8 Figure 8 KNM-KP 293080; Colobinae gen. et sp. indet.

B, left mandible, occlusal view; scale 5 2 cm

there is some degree of sexual dimorphism. Para-papio was the most common cercopithecid in theSouth African Pliocene and early Pleistocene siteswhere P. jonesi Broom, 1940, P. broomi Jones,1937, and P. whitei Broom, 1940, are recognized.In East Africa, Parapapio is less well known but,prior to the appearance of Theropithecus, is thedominant cercopithecid at most Pliocene sites in theTurkana Basin (e.g., Allia Bay, Kanapoi, and Lo-mekwi). Parapapio ado (Hopwood, 1936) is rec-ognized at Laetoli, Tanzania (Leakey and Delson,1987) and Parapapio cf. P. jonesi at Hadar (Frostand Delson, 2002).

Parapapio ado (Hopwood, 1936)(Figure 9; Tables 5–8)

KANAPOI MATERIAL. 286, male mandibularsymphysis (roots Lt. and Rt. I1–/C), Lt. mandibularfrags (P4–M1), (M3), Rt. mandibular frag (M2–3);26942, Rt. mand (M1–3); 29295, Rt. M2; 29304, Lt.mand frag (worn M1–2, M3 talonid); 29305, Rt. M3;29306, male Lt. mand (P3–M3, root /C, alveoli Lt.and Rt. I1–I2); 29310, Rt. M2; 29312, Lt. mand frag(M2–3), Lt. P4, mand and tooth frags; 30147, maleedentulous mandibular symphysis (roots Lt. andRt. C, P3, alveoli Lt. and Rt. I1–2), frags Lt. man-dible (roots M1–3); 30148, Rt. female C/; 30149,juvenile mand (Lt. d/C, dP3–4, M1, Rt. dI2–M1), Lt.juvenile max (dC/, dP3–4, M1, C/ in crypt), Rt. ju-venile max (dP3–M1) isolated Lt. and Rt. dI1, I1, Rt.dC/, skull frags; 30213, Rt. M2; 30230, female Rt.mand (P3–M3), Lt. mand (M1–3), isolated Lt. andRt. I1, I2 and Lt. P3; 30233, Lt. male mand (M3,roots /C–M2), Rt. mand frag (root /C); 30398,worn and broken Rt. M2 and mand frag; 30399,Rt. M3; 30434, Rt. dI1; 30483, Lt. M3; 30531,squashed anterior female mand (broken Lt. and Rt.I1–P4); 30532, Lt. mandible (broken P4–M2);30535, Rt. M3; 29311, Lt. I2; 30538, female max,mand, and skull frags: Rt. mandible (broken and


Figure 9 KNM-KP 29306; Parapapio ado, left male mandible (P3–M3), A 5 lateral view; B 5 medial view; C 5 occlusalview; scale 5 3 cm

cracked I1–M3), Lt. mandible (I2–M1), Lt. I1, M3,/M; Lt. maxilla (I1–P3) broken Rt. C/, broken Lt.P4, M1, M2, M3; 30539, Rt. M1; 32512, Lt. M3;32520, female edentulous mand (roots Lt. I1–M1

and Rt. I1), Rt. I2; 32527, Lt. dP4; 32534, Rt. M1

or M2; 32535, Rt. M2; 32554, Rt. male C/; 32572,Lt. dP4; 32804, mesial frag Lt. M3; 32805, partialRt. M1; 32806, Rt. M3; 32811, broken Rt. M3;32816, Rt. I1; 32817, worn Rt. M3; 32819, Rt. max(P3–4), frag edentulous Lt. premax; 32869, Rt. M3,and Lt. /C; 32878, Rt. dP3; 32884, Lt. d/C; 36914,Lt. M2, partial /M; 36969, Rt. female /C, M frag,Lt. P4; 37374, tooth frags—molar and premolar up-per and lower, dist phalanx; 37378, broken M,tooth frag; 37379, Lt. /I, talonid Lt. M3; 37380,broken Lt. I2; 43121, Rt. female /C; 43122 dP4.

The Kanapoi Parapapio material is rather frag-mentary and consists mainly of isolated teeth. Twomandibular specimens are well preserved in addi-tion to the mandible KP 286 that was recovered bythe earlier expeditions and initially attributed toParapapio jonesi (Patterson, 1968). KP 29306, amale left mandibular body, includes the entire sym-physis extending to the right canine alveolus. Thesymphysial morphology is close to that of KP 286,although it is shallower and in profile less steeplyinclined with a slight curvature. The body is notdeep and is quite slender with well-preserved P3–M3. KP 30147 is a mandibular symphysis that hassuffered some postmortem expansion, making itappear larger than KP 286. If allowance is made

for the distortion, the symphysial morphology issimilar to the other two specimens. All three man-dibles have a distinct mental foramen and may bedistinguished from Pliopapio alemui by the steeplysloping symphysis and the angle of the incisorroots, which shows the incisors to have been pro-cumbent rather than vertically set. Two specimens,KP 30149 and KP 30538, have well-preserved up-per and lower juvenile dentitions.

The M3 has an unusually large talonid and tal-onid basin, such that the hypoconulid is of almostequal size or in some cases (KP 30233) larger thanthe distal lingual cusp (entoconid). This feature,which occurs with a relatively high frequency atKanapoi but is unusual in other species of Para-papio, may possibly be of taxonomic significance.

Theropithecus Geoffroy, 1843Theropithecus first appears in the Turkana Basinabout 3.5 million years ago, although one oldertooth from Allia Bay may possibly represent thisgenus and a partial tooth from Kanapoi is here as-signed to Theropithecus. At Pliocene localitiesyounger than 3.5 million years, T. brumpti (Ar-ambourg, 1947) became the dominant cercopithe-coid until it was replaced by T. oswaldi (Andrews,1916) at about 2.5 million years (Leakey, 1993).

cf. Theropithecus sp. indet.KANAPOI MATERIAL. 32879, broken Rt.

M1or2.

52 m CS 498, Harris and Leakey: KanapoiT

able

5K

anap

oiPa

rapa

pio

ado

uppe

rte

eth

mea

sure

men

ts

Side

I1

MD

LL

I2

MD

LL

C/

MD

LLH

eigh

t

P3

MD

BL

P4

MD

LL

M1

MD

BL

M2

MD

BL

M3

MD

LL

2931

029

311

3014

830

149

3014

9

Fem

ale

R L R7.

57.

56.

0;

5.8

4.2

;4.

8

5.3

4.4

6.8

6.8

10.9

9.3

9.3

8.1

8.0

9.6

9.3

3053

830

538

3251

232

534

Fem

ale

L R L

6.5

6.1

.3.

94.

9.

6.3

.5.

95.

66.

75.

05.

77.

08.

29.

8

.10

8.6

9.5

10.6

9.5

10.1

3280

532

819

3255

436

969

R R L11

.68.

8.

5.3

7.1

5.3

5.6

7.4

7.4

8.3

.6.

8

This tooth is larger than any of the Parapapiofirst and second molars (MD length 11.6; BL distalbreadth 8.0). It is incomplete, lacking most of thelateromesial cusp both mesial and lateral to the pre-served cusp tip. The deep valleys and high cuspsindicate affinities with Theropithecus. As such, thisis one of the earliest occurrences of this genus.

Cercopithecidae gen. et sp. indet.(Figure 10)

KANAPOI MATERIAL. 458, prox Lt. ulna, distfemur; 29292, partial Lt. femur shaft; 29303, distRt. humerus; 29309, Lt. astragalus; 30424, proxRt. femur; 30431, prox Rt. radius; 30460, prox Lt.femur; 30529, prox Rt. femur; 32516, Lt. C/;32562, phalanges, phalanx shaft, prox m/p, patella,rib frags; 32818, frags of calcaneum, femur head,long bone frags; 32880, caudal vertebra; 36601,proximal phalanx; 36831, prox Lt. ulna frag;36834, distal Rt. humerus; 36837, Rt. astragalus.

A complete, slender, high-crowned canine (KP32516) represents a small monkey. Crown mea-surements are MD length, 3.9; LL width, 6.3; maxcrown height, 13.0. The height of the crown sug-gests it must be from a male. The size is too smallfor it to belong to the Kanapoi Parapapio. It maypossibly be referable to cf. Cercopithecoides sp. in-det., the small colobine described above, but theslender nature of the canine is unlike other colobi-nes. For now it is left as Cercopithecidea gen. et sp.indet.

Two fragments of distal humerus are morpholog-ically similar but very different in size. The medio-lateral width of the smaller, KP 29303, is 22.5 mm,in contrast with the larger KP 36834, which mea-sures 30.4 mm. Both are reasonably well preservedalthough, on both, there is some weathering of themedial epicondyle and along the lateral edge of thecapitulum. The trochlear flange is relatively lightlydeveloped and the olecranon fossa elongated later-omedially, quite deep but not perforated. Com-pared with the Parapapio lothagamensis humeri de-scribed from Lothagam (Leakey et al., 2003), themedial epicondyle is less posteriorly directed, thetrochlear flange less strongly developed, and theolecranon fossa more elongated lateromediallywithout any proximal extension to accommodatethe ulna olecranon process in extension. The distalhumerus of Cercopithecoides is closer in all thesecharacters to those from Lothagam than to the twospecimens from Kanapoi.

Two partial ulnae were recovered, KP 458 andKP 36831. The former is well preserved, small,lightly built, and most probably colobine. Its shortolecranon process is slightly deflected posterome-dially. The radial notch appears to show some in-dication of a double articular facet. KP 36831 isslightly larger, less well preserved, and squashed,but is morphologically similar to KP 458.

The shaft of the proximal radius, KP 30431, ex-tends 30 mm below the radial tuberosity. The ar-

Harris, Leakey, Cerling, and Winkler: Tetrapods m 53T

able

6Pa

rapa

pio

ado

low

erde

ntiti

onm

easu

rem

ents

Side

I 1

MD

LL

I 2

MD

LL

/C

MD

LLM

axhe

ight

P 3

MD

BL

Hei

ght

P 4

MD

BL

M1

MD

BL

M2

MD

BL

M3

MD

LL

0028

600

286

0694

209

295

0930

4

Mal

eM

ale

L R R R L

;5.

810

.0.

5.8

6.1

7.8

8.4

6.6

7.3

7.2

6.4

10.8

11.3 9.5

8.7

8.4

9.1

8.1

8.0

12.5

12.2

13.8

9.7

9.1

9.0

2930

529

306

2931

230

149

Mal

eR L L L R

7.8

4.9

15.3

6.7

5.5

8.1

8.1

8.3

6.6

;6.

8

10.0

11.4

8.2

9.4

10.9

11.5

12.1

7.3

8.8

9.0

3021

330

230

3023

330

398

Fem

ale

Fem

ale

R L R L R

4.2

4.1

5.2

5.3

3.6

3.9

5.2

5.4

.6.

16.

54.

34.

34.

36.

97.

610

.410

.2

10.4 8.3

8.3

10.5

8.1

11.8

.11

.7

,8.

7

8 12.9

7.9

8.8

3039

930

483

3053

130

532

Fem

ale

R L L L6.

57.

6.

6.4

13.3

13.0

8.7

9.1

3053

530

538

Fem

ale

Fem

ale

R L R4.

34.

45.

35.

63.

53.

45.

45.

63.

56.

25.

3.

3.9

6.5

6.1

.5.

55.

37.

29.

511

.713

.2 8.5

11.9

9.0

3053

932

520

3253

532

804

3280

6

Fem

ale

R R R L R

3.6

4.6e

8.8

6.5

9.1

8.0

10.9

8.7

7.4

3281

132

816

3281

732

869

3286

9M

ale

Mal

e

R R R L R

4.3

4.8

6.4

8.8

.14

.1

12.3

10.9

12.1

7.8

.8.

536

914

3696

937

379

3738

043

122

L R R L R

4.0

5.5

.4.

2

3.9

7.7

6.4

3.2

9.9

8.4


Table 7 Parapapio ado deciduous teeth

Side

dI1

MD LL

dI2

MD LL

dC/

MD LL Height

dP3

MD BL

dP4

MD BL

Upper dentition

3014930149304343257232878

LRRLR

6.06.15.8

3.63.43.6

5.25.2

3.73.6

7.56.8

7

6.06

6.3

8.58.5

7.3

6.96.9

6

Side

dI1

MD LL

dI2

MD LL

d/C

MD LL Height

dP3

MD BL

dP4

MD BL

Lower dentition

3014930149325273288443122

LRLL

4 2.8 3.53.6

2.9

4.24.3

4.3

.5.2 6.86.9

4.54.4

7.176.8

6.5

5.965.5

5.2

Table 8 Kanapoi Parapapio ado mandibular measure-ments

29306

Depth below P4/M1 junctionDepth below M2/M3 junctionMax thickness below M1

Max thickness below M3

Length tooth row P3–M3

27.124.799.3

35.4

ticular surface of the head is almost circular, witha distinct depression for articulation with the hu-merus capitulum. It is tilted with the posteriomedialedge higher than the opposite side; the anterolateralportion of the collar surrounding this depression iswidest. The head measures 15.5 mediolaterally by14.5 anteroposteriorly. The radial tuberosity is welldeveloped with a raised and rounded anterior bor-der and a less prominent crest marking the poste-rior margin. The interosseous crest commencesabout 10 mm below the most distal extent of theradial tuberosity.

Three fragments of proximal femora, KP 30460,30424, and 30529, and a proximal femur shaft, KP29292, have been recovered. 30460 has lost themargins of the greater tuberosity, 30424 lacks thehead, and 30529 has lost both the greater and less-er tuberosities. KP 458 is a distal epiphysis withapproximately 25 mm of shaft. The neck of KP30424 is relatively long compared with those of theLothagam femora, and the articular surface of theslightly larger head projects onto the femoral neck.The greater tuberosity of KP 30460 is relativelylarge and would have extended proximal to thehead. KP 30529 is significantly smaller than theother fragments. The proximal shaft KP 29292 has

a pronounced crest on the posterior face proximalto the commencement of the linea aspera.

Two complete tali were recovered. The maxi-mum length of the smaller, KP 29309, is 23 mm;that of the larger, KP 36837, is 27 mm. KP 29309has a carnivore tooth mark on its trochlear surface.Both specimens have relatively long necks.

The affinities of the postcranial elements are un-clear. In general, they appear to be from similarsized individuals, but the size discrepancy betweenthe two morphologically similar distal humeri sug-gests these elements may represent one sexually di-morphic species.

DISCUSSION

Sites close in age to Kanapoi that have yielded earlycercopithecids include Aramis (4.4 Ma), Allia Bay(3.9 Ma), Laetoli (3.6 Ma), and the Sidi Hakoma(3.4–3.22 Ma), Denen Dora (3.22–3.18 Ma), andlower Kada Hadar (3.18–2.92 Ma) members of theHadar Formation in the Awash Valley. Aramis isunusual in having a larger proportion of colobinesto cercopithecines (56% colobines). Only two cer-copithecoid species are recognized from Aramis—Kuseracolobus aramisi Frost, 2001, and Pliopapioalemui. Neither is represented at Kanapoi. The Al-lia Bay cercopithecids are largely represented byisolated teeth that are difficult to assign taxonom-ically. However, papionins far outnumber colobi-nes. At Laetoli, the common cercopithecid is Par-apapio ado, although cf. Paracolobus sp. is also rel-atively common. Unfortunately there are no wellpreserved P3s in the Laetoli assemblage that can becompared with the two differing large colobine P3sfrom Kanapoi. It is possible that one of the Kana-poi colobines is the Laetoli species. Present but un-common at Laetoli was a small indeterminate co-


Figure 10 Cercopithecidae gen. et sp. indet., postcranial elements; distal right humerus: A,C 5 KNM-KP 29303, B, D5 KNM-KP 36834; A, B 5 posterior view, C, D 5 anterior view; E 5 KNM-KP 458, proximal left ulna, F 5 KNM-KP 36831, proximal left ulna; G 5 KNM-KP 30431, proximal right radius, E, F, G 5 lateral view;. H, I 5 KNM-KP30424, proximal right femur, H 5 anterior view, I 5 posterior view

Table 9 Kanapoi Deinotherium bozasi tooth measure-ments

AccessionNo. 401 30152

Lt. M2 approtmet

92.192.490.8

Lt M3

Lt. M3

approtmetapprotmet

96.599.090.1

87.579.967.9

lobine and a large papionin cf. Papio sp. (Leakeyand Delson, 1987). The cercopithecids from Hadarinclude Theropithecus darti (Broom and Jenson,1946) and Parapapio cf. P. jonesi, as well as thecolobines Rhinocolobus turkanaensis Leakey M.

G., 1982, and a new species of Cercopithecoides(Frost and Delson, 2002).

Family Hominidae

Australopithecus Dart, 1925

Australopithecus anamensisLeakey et al., 1995

KANAPOI MATERIAL. 271, distal Lt. humerus;29281, holotype mandible and Lt. temporal;29282, Lt. M1/2; 29283, maxilla; 29284, Rt. P3 andRt. /C germs; 29285, Rt. tibia lacking midshaft re-gion; 29286, mandible fragments and associatedlower teeth (Rt. I1, Lt. and Rt. I2–M3); 29287, man-dible with teeth; 30498, Lt. and Rt. maxilla frag-ments and associated dentition; 30500, mandibularfragments and associated dentition (Rt. I2–P4,M2–3); 30502, Rt. M3, partial Lt. /M, molar frags;30503, proximal manual middle phalanx; 30505,broken molar germ; 30942, five molar frags;31712, associated juvenile mandibular and dentalfragments; 31713, Rt. mandible with tooth frag-


ments; 31714, Lt. dP4; 31715, Lt. M1/2 and twoassociated tooth frags; 31716, P3/4 fragment and C/frags; 31717, Lt. M3, Rt. M3, and Lt. M2 frags;31718, Rt. mandible frag (M2–3); 31719, I1; 31720,maxillary M fragment; 31721, Rt. M2 and M3 par-tial crowns; 31723, Rt. M3; 31724, Lt. capitate;31726, Rt. P4; 31727, Rt. /C; 31728, Lt. M1;31729, Rt. dP2; 31730, Lt. M2, Rt. P3; 31732, toothfrags; 34725, associated juvenile dentition and skullfrags; 35838, Lt. M3; 35839, Lt. I1, Rt. C/, and Lt.P3; 35840, Lt. M3 and upper tooth frags; 35841,M crown; 35842, Rt. M?1or?2; 35844, M frag;35845, M frag; 35847, Lt. M2; 35850, M/ frag;35851, Lt. M1/2 frag; 35852, Lt. C/; 37522, Lt. /M;37523, M frag; 37524, tooth frags.

Australopithecus anamensis is distinguished fromall other australopithecine species by the followingfeatures: a small external acoustic meatus present-ing a narrow ellipse in outline; long axes of man-dibular bodies and tooth rows nearly parallel andclose together; mental region of mandible notstrongly convex; long axis of symphysis slopesmarkedly posterioinferiorly; canines with very longrobust roots, trigons of upper molars much widerthan talons, distal humerus with thick cortex en-closing a small medullary cavity. It can be distin-guished from A. afarensis Johanson et al., 1978, bythe following: upper canine root and associated fa-cial skeleton less posteriorly inclined; lower molarstend to have more sloping buccal sides and uppermolars more sloping lingual sides; tympanic platehorizontal without defining grooves. It can be dis-tinguished from Ardipithecus White et al., 1994, bythe following features: absolutely and relativelythicker enamel; upper canine buccal enamel thick-ened apically; molars more buccolingually expand-ed; first and second molars not markedly differentin size; tympanic tube extends only to the medialend of the postglenoid process, rather than to thelateral edge or beyond it; lateral trochlear ridge ofhumerus weak (Leakey et al., 1995).

Australopithecus anamensis is the oldest reliablydated Australopithecus species. It was a habitualbiped and is readily distinguishable from A. afar-ensis to which it may have been ancestral. A de-tailed account of the Kanapoi material, and ofslightly younger material of A. anamensis from Al-lia Bay, was provided by Ward et al. (2001).

Order Proboscidea

Family Deinotheriidae

Deinotheres are Neogene proboscideans that dif-fered from gomphotheriids and elephantids by re-taining only the lower tusk and by never developinghorizontal tooth replacement for their low-crownedlophodont teeth. Adapted for browsing on forestvegetation, they were common elements of the earlyMiocene African assemblages but are encounteredonly in small numbers in Pliocene and Pleistoceneassemblages.

Deinotherium Kaup, 1829

Deinotherium bozasi Arambourg, 1934(Table 9)

KANAPOI MATERIAL. 388, enamel frags andpostcranial elements; 393, atlas; 401, Lt. M2 andM3; 30152, Lt. M3; 30557, partial M.

Deinotherium bozasi was a large African dein-othere with teeth of similar size to the Europeanspecies Deinotherium giganteum Kaup, 1829. Theskull rostrum was steeply downturned anteriorly(like that of Prodeinotherium hobleyi [Andrews,1911]) but the external nares and rostral troughwere narrower than in D. giganteum. As in P. hob-leyi but in contrast with D. giganteum, the preor-bital swelling is reduced and situated just in frontof P3, the occiput is steeply inclined, and the nasalbones have a slight anterior median projection(Harris, 1978).

Deinotheres are represented at Kanapoi by a cou-ple of isolated teeth and, perhaps, by ribs and ver-tebrae of a juvenile proboscidean that were asso-ciated with unerupted deinothere enamel frag-ments. The upper second and third molars are dis-tinctly smaller than the equivalent teeth on thesomewhat younger D. bozasi skull from KoobiFora (Harris, 1976a) and the lower third molar issmaller than the equivalent tooth in early Pleisto-cene deinotheres.

Family Gomphotheriidae

Gomphotheriids were the common proboscideansin African Miocene assemblages but only Anancuslingered into the early Pliocene.

Anancus Aymard in Dhorlac, 1855

Anancus kenyensis (MacInnes, 1942)(Table 10)

KANAPOI MATERIAL. 384, Lt. M2; 410, Lt.M2, Lt. and Rt. M3.

Anancus kenyensis has been diagnosed by Cop-pens et al. (1978) as ‘‘a progressive species of An-ancus with four and one half to five or more conepairs on M2 and five and one half or more on M3;the crown is complicated by the presence of enamelcolumns partially fused into the faces of the maincones.’’

Anancus kenyensis is the last gomphotheriid spe-cies to survive in sub-Saharan Africa. Three An-ancus teeth were recovered from Kanapoi by thePatterson expeditions of 1965 and 1966. Tassy(2003) recognized two different populations of A.kenyensis—a primitive or kenyensis morph with te-tralophodont second molars based on the holotypeof A. kenyensis, from Kanam (MacInnes, 1942)and a derived or A. k. petrocchi morph with pen-talophodont second molars based on the samplefrom Sahabi (Libya) described by Petrocchi (1954).The A. kenyensis morph was recognized in samplescollected from Kanam, Lukeino, Mpesida, and


Table 10 Kanapoi Anancus kenyensis tooth measurements

Accession No. 384 410 410 410

ToothNo. platesNo. plates in wear

LM2

55

LM2

55

RM3

63

LM3

LengthLength wear surfaceWidth (greatest)Height (middle plate)

156.25

75.8967.54

146.6

68.64

22091.68160.9

7964.09

Enamel thickness 5.04

Lothagam, whereas the A. k. petrocchi morph isrepresented at Sahabi (Libya) and at Aterir, and inthe Chemeron Formation in the Baringo Basin, aswell as at Lothagam. The second molars recoveredfrom Kanapoi display the derived traits—accessoryconules, fifth lophid, and strong anancoidy—thatare characteristic of the A. k. pettrochi morph (Tas-sy, 2003).

Family Elephantidae

The Family Elephantidae originated in the lateMiocene of Africa. Stegotetrabelodon Pettrochi,1941, and Primelephas Maglio, 1970, are the dom-inant elephantids at Lothagam (Tassy, 2003). Ele-phas ekorensis Maglio, 1970, first appears in theApak Member at Lothagam together with an earlyLoxodonta F. Cuvier, 1925, species. Elephas eko-rensis, and Loxodonta adaurora appear to be thecharacteristic elephantids of the African early Pli-ocene.

Elephas Linnaeus

Elephas ekorensis Maglio, 1970(Figure 11; Tables 11, 12)

KANAPOI MATERIAL. 382, Rt. P4 frag; 392,P2; 395, M3 frag; 400, mand (P2); 409, Rt. and Lt.mand frags (M2); 411, Lt. M3 frag; 412, M2; 452,Rt. P3; 28442, Lt. and Rt. P3 frags; 30189, Lt. M3;30197, skull (RP2–3, Lt. P2–3); 30236, M3; 30404,Rt. and Lt. P3–4, skull frags; 30625, M1 frag andunerupted M2 frags; 30639, mand (Rt. M2, Lt.M1–2); 32575, Lt. mandible (P3–4); 30198, Lt. mand(M1–2); 387, RM3; 26956, Rt. mand (M1); 30169,Lt. juv mand (P2–3); 30170, Lt. juv mand (P3) andsymphysis; 30173, Lt. mand frag (P3), frags un-erupted P4; 30175, mand (Lt. P3, dP4, Rt. P4);30270, Lt. and Rt, P2–4 and tusk frag eaten by hy-ena; 30471, Lt. mand (M2 and M3) and symphysis;38975, Rt M3.

Elephas ekorensis is an early species of Elephasthat was diagnosed by Maglio (1973) as havingmolars with crown height 10–15% greater thanwidth, M3 broad anteriorly, becoming very narrowposteriorly; greatest width at base of crown; enamelloops prominent; enamel only very weakly foldednear the base, 3–4 mm thick. The enamel plates are

well separated with lamellar frequency of 3.8–4.8.The plate formulae are M3 11/12, M2 ?/?, M1 7/8(Maglio, 1973).

Elephas ekorensis and Loxodonta adaurora arethe two common proboscideans from Kanapoi. Theteeth of E. ekorensis may be generally distinguishedon the basis of their narrower width, greater num-ber of plates, greater lamellar frequency, and thin-ner and more convoluted enamel (Fig. 11). Unworntooth plates have more apical digitations than thoseof Loxodonta teeth. Mandibles of E. ekorensis areproportionately narrow; the ventral surface is hor-izontal but curves down in front of the symphysisto terminate in a beak, which curves abruptly an-teroventrally and is smaller and more gracile thanthat of L. adaurora. The upper second premolarsometimes has two plates (KP 30197) but the lowerhas three (KP 30150). The third premolars have sixplates and are wider posteriorly. The fourth pre-molar and first molar have eight plates.

Elephas ekorensis is one of the oldest recognizedspecies of Elephas. It has been recovered from theApak Member of the Nachukui Formation at Loth-agam, where it is preceded in the Upper NawataMember by Elephas nawataensis Tassy, 2003, whichTassy (2003) interprets as intermediate between theearlier Primelephas gomphotheroides Maglio, 1970,and E. ekorensis.

Loxodonta F. Cuvier, 1825

Loxodonta adaurora Maglio, 1970(Figure 12; Tables 13, 14)

KANAPOI MATERIAL. 381, Lt. and Rt. mand(M1); 383, Lt. and Rt. M3; 383, Lt. M3 and frags;385, holotype mand and skeleton; 389, M3 frags;390, Rt. and Lt. M3 frags; 391, M1 frag and pc;394, radius and ulna; 396, Rt M2; 403, mand (Lt.M2–3), pelvis, and femur; 406, Rt. mand frags(M1–2); 407, RM3; 548, Lt. M3 frags; 28441, M2

frag; 30150, P2; M2or3 talonid; 30188, Rt. maxilla(worn M3); 30191, max frag (Lt. M3); 30193, Lt.and Rt. mand (M3) and frags; 30204, skull (Rt.and Lt. M3), damaged posteriorly; 30269, mand(Rt. and Lt. M2–3); 30436, P2; 30596, mand M?3

(needs preparation); 30616, mandible (Lt. and Rt.


Figure 11 KNM-KP 30175; Elephas ekorensis mandible with Lt. P3, P4, Rt. P4, occlusal view; scale 5 5 cm

P3, P4); 30654, Rt. M3; 32542, mand (Rt. and Lt.M2–3).

Loxodonta adaurora was diagnosed by Maglio(1970) as a Loxodonta species with low-crownedmolars, height equal to or less than width; enamelnot folded, 3–5 mm in thickness; very large ante-rior and posterior columns, partially fused intoplates but free at their apices, forming prominentmedian loops with wear; plates thick and well sep-arated, lamellar frequency from 2.6 to 4.4. Theplate formulae: M3 8–10X/10–11x, M2 7–8x/6–8x, M1 7/6–7 dm4 5/5–6, dm3 5/5–6, dm2 3/3(Maglio 1973).

The holotype of Loxodonta adaurora, a skulland partial skeleton, was collected from Kanapoiin 1965 and described by Maglio in 1970 but un-fortunately was badly damaged during its subse-quent transportation back to Kenya. Some lesscomplete specimens were collected by NationalMuseums of Kenya expeditions during the 1990s.In general, L. adaurora teeth may be distinguishedfrom those of E. ekorensis because they are wider,have fewer plates, and have thicker and less con-voluted enamel; unworn tooth plates have a pos-terior median pillar and fewer apical digitations.The horizontal ramus of the mandible tends to bebulbous because of the greater width of the L.

adaurora teeth. The ventral surface of the man-dible curves downward anteriorly at the rear ofthe symphysis to terminate in a robust beak. Thecusps of the second premolars tend to remain iso-lated rather than fused into transverse plates.Fourth premolars and first molars have sevenplates.

Loxodonta exoptata (Dietrich, 1941)(Figure 13)

Kanapoi Material. 30611, Rt. mandible (M2).Loxodonta exoptata was originally recognized

from the 3.5 Ma Laetolil Beds of Laetoli in Tan-zania (Beden 1987). The teeth are more hypsodontthan those of L. adaurora and have more plates butthinner enamel. In early wear, the plates form a lox-odont pattern strongly reminiscent of the extant L.africana (Blumenbach, 1797). Molar fragments at-tributed to Loxodonta aff. L. exoptata have beenrecovered from the Apak Member at Lothagam(Tassy, 2003).

A partial mandible with lower second molarfrom high in the succession is the sole representa-tive of Loxodonta exoptata from Kanapoi. It haseight plates, each with a posterior median pillar,


Table 11 Kanapoi Elephas ekorensis upper teeth measurements

Accession No. 30197 30197 382 30197

ToothNo. platesNo. plates in wearLength

LP2

24.75

RP2

512

23.57

LP3 LP3

66

68.7Length wear surfaceWidth (widest plate)Height (middle plate)Enamel thicknessLaminar frequency

23.1216.7521.2937.741.79E

40.2462.3

10

Accession No. 30197 30404 30404 30404 30404


RP3

66

70.54

LP3

66

60.4

RP3

66

62.11

LP4

511

RP4

511

Length wear surfaceWidth (widest plate)Height (middle plate)Enamel thicknessLaminar frequency

57.7643.44

1.7310

59.4540.68

1.849

59.3339.6342.582.149

8.4251.7442.67

6

9.5952.43

2.396

Accession No. 412 387 411 30189


LM2

714

M?3 RM3 LM3


122.8777.9599.052.9

5E4.5

80.18E

3.3441

77.69

5.425.5

85.42

4.245

Accession No. EK 424 EK424


RM3

101?

2691

LM3

124

280Length wear surfaceWidth (widest plate)Height (middle plate)Enamel thicknessLaminar frequency

91112

5

128.1195.46

120.065.155

and thick enamel. The rear of tooth is wider thanthe front.

Order Perissodactyla

Family Rhinocerotidae

The extant genera Ceratotherium Gray, 1867, andDiceros Gray, 1821, first appear in the late Mio-cene but at Lothagam are accompanied by the te-leoceratine rhino Brachypotherium Roger, 1904(Harris and Leakey, 2003b). Thus far, only the ex-tant genera have been recovered from Kanapoi.

Ceratotherium Gray, 1867

Ceratotherium praecoxHooijer and Patterson, 1972

(Figure 14; Table 15)

KANAPOI MATERIAL. 30, Rt. nasal boss, oc-ciput frag, and skull frags; 32, incomplete rami (Lt.and Rt. P3–M3); 33, Lt. mand frag (M2); 36, skull(Lt. M2–3, Rt. P4–M3) holotype; 38, Rt. P4 frag,tooth frags; 538, dist Lt m/t III; 30187, partial skull(P3–4); 30195, Lt. humerus; 30217, Lt. mand (P3);30554, Lt. P4; 32556, Lt. dP/ frag; 32868, Lt. P4.

60 m CS 498, Harris and Leakey: KanapoiT

able

12K

anap

oiE

leph

asek

oren

sis

low

erte

eth

mea

sure

men

ts

Acc

essi

onN

o.40

030

169

411

3016

930

170

3017

330

175

3257

5

Toot

hN

o.pl

ates

No.

plat

esin

wea

rL

engt

h

LP 2 4 none

25.7

6

LP 2 4 2 26.1

4

LP 3 6 6 66.5

31

LP 3 6 1 68.1

LP 3 6 none

62.6

6

LP 3 6 6 70.3

3

LP 3 51

Lt.

P 3

5 5L

engt

hw

ear

surf

ace

Wid

th(w

ides

tpl

ate)

Hei

ght

(mid

dle

plat

e)E

nam

elth

ickn

ess

Lam

inar

freq

uenc

y

none

19.5

915

.21

20E

11.5

818

.79

0.97

20E

66.5

3

1.6

9E

5.53

40.5

130

.05

9E

none

42.4

632

.26

2.79

9E

62.6

941

.86

1.71

9E

39.7

4

1.97

10E

24.

2.3

13

Acc

essi

onN

o.28

442

3017

530

175

3257

540

926

956

Toot

hN

o.pl

ates

No.

plat

esin

wea

rL

engt

h

Lt

P 4 8 8 68.6

LP 4 9 5

113.

2

RP 4 9 5

116.

95

Lt.

P 481 3

106E

LM

1

8 116

7E

RM

1

71 312

0.46

1L

engt

hw

ear

surf

ace

Wid

th(w

ides

tpl

ate)

Hei

ght

(mid

dle

plat

e)E

nam

elth

ickn

ess

Lam

inar

freq

uenc

y

36.7 2 8

62.5

850

.6 2.5

72.8

453

.43

2.57

8

25 2.5

9E

24.0

759

.99

71.0

33.

616.

5

54.1

57.7

76.1

2.72

6

Acc

essi

onN

o.30

198

3063

930

198

3063

9

Toot

hN

o.pl

ates

No.

plat

esin

wea

rL

engt

h

LM

1

51

Rt.

M1

8 813

5

LM

2

3

Lt.

M2

9x

179

Len

gth

wea

rsu

rfac

eW

idth

(wid

est

plat

e)H

eigh

t(m

iddl

epl

ate)

Ena

mel

thic

knes

sL

amin

arfr

eque

ncy

96.1

363

.511

3.41

5E

61 3.56

6.5

54.1

9

4.13

5E

85 5


Tab

le12

Con

tinue

d

Acc

essi

onN

o.30

236

3047

130

625

3897

5

Toot

hN

o.pl

ates

No.

plat

esin

wea

rL

engt

h

Rt.

M3

81

2231

LM

3

13 327

6

Lt.

M3

61R

t.M

3

71 4

Len

gth

wea

rsu

rfac

eW

idth

(wid

est

plat

e)H

eigh

t(m

iddl

epl

ate)

Ena

mel

thic

knes

sL

amin

arfr

eque

ncy

100 4.

23.

5

75.7

986

.47

105.

75.

055

75 95e

4.5

5

801 4 4.5

Ceratotherium praecox appears to have been theprecursor of the extant white rhino. As diagnosedby Hooijer and Patterson (1972), the cranium dif-fers from that of C. simum (Burchell, 1817) by thegreater concavity of skull roof, cranium less ex-tended posteriorly, occiput more vertically inclined;cheek teeth not as hypsodont, lophs and lophidsnot markedly oblique, anterointernal corners of up-per teeth not rounded, no medifossettes in P2–M2

and no fossettids in lower cheek teeth, internal cin-gula in upper cheek teeth variable. Ceratotheriumpraecox has been recovered from throughout theKanapoi sequence.

The holotype of C. praecox is a relatively com-plete cranium from Kanapoi (KP 36; Hooijer andPatterson, 1972) but the Kanapoi material is in gen-eral much less well preserved than the abundantmaterial of this species that was subsequently de-scribed from Langebaanweg (Hooijer, 1972). New-ly recovered material includes KP 30187, an incom-plete cranium including part of the left maxilla withdP2–3, part of the anterior cranial vault with ante-rior part of left zygomatic arch, and the occiputdorsal to the foramen magnum. The specimen dis-plays primitive characters for Ceratotherium in thatthe occiput is still vertical and not backwardly in-clined as in C. simum, the posterior part of the cra-nial vault is flat and rising upward as in Diceros,and although the length from the orbit to the nu-chal crest cannot be measured because the bone isnot continuous it was evidently much greater thanin the Lothagam examples of Diceros. The pre-molar lophs are more transversely oriented than inthe extant C. simum.

Diceros Gray, 1821

Diceros bicornis (Linnaeus)(Figure 14; Table 16)

KANAPOI MATERIAL. 30216, Lt. P2; 30472,Lt. P3; 40, max frags (Lt. dP3); 39, Rt. humerus.

As at most Pliocene and Pleistocene sites in sub-Saharan Africa, Diceros was not a common ele-ment of the Kanapoi biota but it is represented byseveral isolated teeth and a nearly complete righthumerus. Older Diceros material has been recov-ered from the Upper Nawata and Apak Membersat Lothagam.

The presence together of Ceratotherium praecoxand Diceros bicornis, the latter being less common,is characteristic of Pliocene and early Pleistocenesites in East Africa. Brachypotherium lewisi Hooi-jer and Patterson, 1972, persists into the ApakMember at Lothagam but has not been found atKanapoi or in the temporally equivalent Kaiyu-mung Member at Lothagam.

Family Equidae

Subfamily Equinae

Hipparionine horses of the genus Hippotherium vonMeyer, 1829, first appear in Africa between 10 and


Figure 12 KNM-KP 30616; Loxodonta adaurora mandible with Lt. and Rt. P3, P4, occlusal view; scale 5 5 cm

11 million years ago. A second wave of migration,this time of the genus Eurygnathohippus van Hoe-pen, 1930, took place about 7 million years ago(Bernor and Harris, 2003). Equid material retrievedfrom Kanapoi represents only the latter genus.

Eurygnathohippus van Hoepen, 1930

As pointed out by Bernor and Harris (2003), allAfrican hipparions of the genus Eurygnathohippusare united by the synapomorphy of ectostylids onthe permanent cheek teeth. Eurasian and NorthAmerican hipparions lack this character except inextremely worn hipparion teeth from the late Mio-cene Dinotheriensandes locality of Germany. Sty-lohipparion van Hoepen, 1932, is the junior syno-nym of Eurygnathohippus by year priority.

Eurygnathohippus sp. indet.(Tables 17, 18)

KANAPOI MATERIAL. 42, Rt. M3; 43, Lt. P2,P4, M1, Rt. P2–M3; 44, Lt. mandible frag (P3–M3);45, m/t frag; 46, Rt. M1 and tooth frags; 47, Lt. P3,M3; 48, Rt. M1; 49, Lt. and Rt. M2–3; 50, M frags;

51, Lt. P3; 52, Lt. P3 and /M frags; 53, Rt. P3; 54,enamel frags; 55, Lt. M2 and /M frag; 56, Lt. P3;57, Lt. P3; 58, Lt. M1–2; 470, M/ frag; 503, enamelfrags; 508, magnum; 518, M frag; 532, Lt. man-dible frags (P2–3, M1–3); 544, Lt. M1; 30167, dist m/p; 30218, Lt. M1–2 and tooth frags; 30220, Rt. M3;30473, Rt. M1 frag; 30476, Rt. P2; 30493, M frags;30555, Lt. P3 and M3; 30556, Rt. P3–M1; 30560,M/ frags; 32809, dI/.

Hooijer and Maglio (1974) recognized threeequid species from Kanapoi and Lothagam thatthey identified as Hipparion turkanense Hooijerand Maglio, 1972, H. primigenium von Meyer,1829, and Hipparion cf. H. sitifense Pomel, 1897.Bernor and Harris (2003) reviewed the Lothagamequids and recognized two common species fromthe Nawata Formation—Eurygnathohippus tur-kanense and the smaller E. feibeli Bernor and Har-ris, 2003. They also attributed a few postcranialelements to Hippotherium cf. H. primigenium.Bernor and Harris noted the great variation intooth mor-phology in the equid teeth from Loth-agam and recommended against naming Plioceneequids from East Africa that were younger in age


Table 13 Kanapoi Loxodonta adaurora upper teeth measurements

Accession No. 30150 406 406 28441 383A

ToothNo. platesNo. plates/wearLength

RP2

33

19.31

RM1 RM2 M2 LM3

92


16.3816.77

20E

69.19

4.835E

72.71

4.5

101

3.54

121109

5.273.5

Accession No. 383B 383C 383E-J 385 385 389


RM3

97

2381

RM3

92

284

?9?6

RM3

108

242

LM3

108

234

M3


21511199414.513.5

96116117

4.484

110

4.48

189105.6

4.693.5E

185108

4.423.5

4.233.5

Accession No. 390 390 30188 30191 30204


RM3

109

2871

LM3 RM3

88

260

LM3

2651

LM3

9141


26111071

6.223.5

4.033.5

3.543.5

7.023.5

125111091e4.183.5

Accession No. 30204 30596


RM3

9141

2441

LM3

7171


130110985e4.064

120

4.53

than the Nawata Formation until appropriatelycomplete diagnostic material had become avail-able. This recommendation seems pertinent for theKanapoi equid hypodigm—given the complete ab-sence of cranial material and that the majority ofKanapoi equids comprise isolated teeth or toothfragments. A few specimens (KP 48, 51, 53, 57)seem a little larger than most while two specimens(KP 49, 30220) seem a little smaller, but it wouldbe unwise to speculate whether such minor differ-ences are meaningful taxonomically.

Order Artiodactyla

Family HippopotamidaeThe earliest known representatives of this familyconstitute teeth from middle and late Miocenesites in Kenya and Tunisia that are assigned to thegenus Kenyapotamus Pickford, 1983. The extantrepresentatives constitute the dwarf hippo Hex-aprotodon liberiensis Morton, 1849, from WestAfrica and the common hippo Hippopotamus am-phibius Linnaeus. Hexaprotodon is the first extant


Table 14 Kanapoi Loxodonta adaurora and L. exoptata lower teeth measurements

Accession No. 30616 30616 381 381 391 406


RP3

x2x

32.4

RP4

76

LM1

6161

RM1

6161

LM1

41RM1

5151


24.417.5

10653.4

2.47

70.44

4.15

72.98

4.25

70663.74.5

70

45

Accession No. 396 403 406 32542 32542


RM2 LM2

41

RM2

6111

RM2

4141

89.36

LM2

4141


85.03

4.254.5E

90.17

5.814

76811

4.5

89.3480.4

4.184

96.7484.4

5.554

Accession No. 385 (type) 385 403 407


LM3

118

279.4

RM3

119

276

LM3 RM3

115


212.4103

4.394

228100.4

5.123.5

93.3798.92

1651001101

3.734

Specimen No. 30193 30654 30611 (5L. exoptata)


LM3

8171

RM3

1111

295

RM2

88


96

5.53.5

110

4.983.5

158E71.88

3.585

genus to occur in the fossil record. Two specieshave been documented by Weston (2003) from thelate Miocene of Lothagam—Hex. harvardi Cor-yndon, 1977, and Hex. lothagamensis Weston,2000. Neither persist into the early Pliocene ofKanapoi where two hippopotamid species are rep-resented—Hexaprotodon protamphibius Aram-bourg, 1944, which is the common Pliocene hippofrom the Lake Turkana Basin, and a smaller un-named species.

Hexaprotodon Falconer and Cautley, 1836

Hexaprotodon protamphibius(Arambourg, 1944)

(Figure 15; Tables 19–21)

KANAPOI MATERIAL. 1, Rt. ramus and sym-physis; 2, upper premolars; 3, Lt. glenoid; 4, /Cfrag; 5, mand frag (P2); 6, Lt. and Rt. mand frags(M1–3); 7, Rt. M3; 8, symphysis and incomplete ra-mus; 9, C, I, foot bones; 10, Rt. C/; 11, max frag


Figure 13 KNM-KP 30611; Loxodonta exoptata, Rt. M2, occlusal view; scale 5 5 cm

(Lt. M2–3); 12, Lt. radio-ulna; 13, distal humerus;14, incomplete forelimb; 15, juvenile Rt. mand (/C,dP4–M1); 16, teeth frags; 17, astragalus; 18, Rt. fe-mur; 20, atlas; 21, Rt. /C frag; 22, cranium; 23,ulna; 24, tusk frags and ramus; 25, C/; 26, M/ andskull frags; 27, P3, M1, roots dP4 in ramus; 28, ra-mus frag (incomplete cheek teeth); 29, incomplete/M; 236, tooth frags; 288, Rt. scapula, ribs andvertebra frags; 289, cervical vertebra; 290, thoracicvertebra; 450, Lt. scapula frags; 456, Rt. /C; 543,m/p, phalanx; 560, mand; 8690, teeth frags; 8696,mand frags; 8700, femur and ulna frags; 8720, cal-caneum and bone frags; 8751, 2nd phalanx; 8752,astragalus; 8753, astragalus; 9910, cranium (M3

erupting); 30153, mid phalanx; 30209, Rt. M2

lacking distal portion; 30210, Lt. M3, tooth andtusk frags; 30211, Lt. M2 broken distally; 30224,

Rt. maxilla (M1–2); 30414, astragalus, calcaneumand prox tibia; 30415, P1; 30488, m/p; 30599, Rt.I3; 30621, C/; 30632, Rt. M1; 30638, cranium andmandible; 31737, phalanx (diseased); 32521, M1;37372, M3, /I, /C.

Hexaprotodon protamphibius was diagnosed byGeze (1980) as a hexaprotodont or tetraprotodonthippopotamus of medium or submedium size. Theskull is relatively narrow with widely separated ca-nine alveoli and orbits little elevated above the fa-cial plane. The lacrimals are enlarged anteriorlyand generally separated from the nasals by the per-sistence of an antorbital process of the frontal. An-terior teeth are small with incisors closely spacedanteriorly; upper canines with deep posterior lon-gitudinal groove; lower canines compressed later-ally with finely striated enamel and subparallel


Figure 14 A 5 KNM-KP 39, Diceros bicornis right humerus; B 5 KNM-KP 30195, Ceratotherium praecox left humerus,posterior view; scale 5 5 cm

Table 15 Kanapoi Ceratotherium praecox teeth measurements

UpperP1 ap

ant trpost tr

30187 LowerP1 ap

ant trpost tr

30217 30554 32868 LT 32L LT 32R

P2 apant trpost tr

P3 apant trpost tr 46.47

P2 apant trpost tr

P3 apant trpost tr

40.5826.74

36.6926.3129.01

P4 apant trpost tr

M1 apant trpost tr

48.9854.88

P4 apant trpost tr

M1 apant trpost tr

46.1530.9832.11

45.6928.95

48E31127.6246.6233.0833.66 30.78

M2 appost tr

M3 apant trpost tr

M2appost tr

M3 apant trpost tr

34.4130.93

31.3232.46


Table 16 Kanapoi Diceros bicornis tooth measurements

41 30216 30472

P1

P2

apant trpost trap

18.9421.83

29.6 36.04

P3

ant trpost trapant trpost tr

33.9838.3336.1744.29148.23

39.3741.59

57.2355.78

Table 18 Kanapoi Eurygnathohippus sp. indet. lowerdentition measurements

42 44 52 55 56

P2

P3

P4

aptraptraptr

27.316.826.716.2

2616.1

25.818.6

M1

M2

M3

aptraptraptr

25.210.4

24.315.425.714.7

2515.2

58 532 30555

P2

P3

P4

aptraptraptr

32.115.1

15.829.317.9

M1

M2

M3

aptraptraptr

23.513.325.612.4

27.414.926.91527.912

2812

Table 17 Kanapoi Eurygnathohippus sp. indet. upperdentition measurements

43 46 47 48 49

P2

P3

P4

aptraptraptr

3523.624.228.122.928.3

27.1

M1

M2

M3

aptraptraptr

22.92522.924.223.422.1

24.523.7

23.821.3

28.128.8

20.519.5120.218.4

51 53 57 544

P2

P3

P4

aptraptraptr

26.725

31.325.21

28.5251

M1

M2

M3

aptraptraptr

25.621.5

30218 30220 30473 30476 30556

P2

P3

P4

aptraptraptr

36.925.8

24.424.221.823.4

M1

M2

M3

aptraptraptr

23.9

23.4

20.320

23.6 22.918.8

ridges. Cheek teeth are aligned in subparallel rows,brachyodont; premolars simple and with few pus-tules, lower premolars often with a linguodistalstylid; quadricuspate molars with poorly developedtrefoils; simple cingulum sometimes bears styles orstylids. Facial region of the skull is larger than cra-nial region. The mandible is massive, longer thanwide, with horizontal rami incurved beneath thepremolars. Limb bones are relatively elongate, ar-ticular surfaces more rounded and interarticularcrests more salient than in Hippopotamus amphi-bius.

The common hippo at Kanapoi is a small hex-aprotodont form of comparable size to Hexapro-todon protamphibius from the lower members ofthe Koobi Fora Formation (Harris, 1991a). Cor-yndon (1977) assigned Kanapoi hippo materialcollected by the Harvard University expeditions toHexaprotodon harvardi, but Weston (1997) com-pared this material to Hex. protamphibius andnoted the similarity of the Kanapoi specimensboth to those from the early part of the KoobiFora Formation and to those from the lower partof the Shungura Formation that Geze (1985) hadassigned to Hex. protamphibius turkanensis (Bois-serie, 2002). Hexaprotodon protamphibius differsfrom the earlier Hex. harvardi from the Nawata


Figure 15 KNM-KP 22; Hexaprotodon protamphibius cranium; A 5 occlusal view; B 5 dorsal view; scales 5 5 cm

Formation and Apak Member of Lothagam be-cause of the size differentiation between the firstand posterior incisors (in Hex. harvardi, they areof equal size) and by its shorter, stockier limbs(Hex. harvardi limbs are larger but more gracile)(Weston 2003). The basicranium is similar to that

of Hex. harvardi and the cheek teeth are of com-parable size but the occiput is less tall and the pal-ate is wider; the mandible of Hex. protamphibiusdiffers from that of Hex. harvardi in that the sym-physis is longer and wider but less tall and thatthe tooth row is narrower (Boisserie, 2002).


Table 19 Kanapoi Hexaprotodon cf. H. protamphibiusskull measurements

22 30638

Length C/ to occipital condyleWidth at caninesWidth at P4

Zygomatic width

560304141373

570330e125370

Table 20 Kanapoi Hexaprotodon cf. H. protamphibiusupper teeth measurements

2 11 22L 22R

I2

I3

P2

aptraptraptr

45e

16.720e16.4e18e

P3

P4

M1

aptraptraptr

41e29.9

3825.63530.6

3231.7

M2

M3

aptraptr

46.8e

47.846.7

5047.64745.9

52e50e4745

26L 26R 9910 30209 30224

P2

P3

P4

aptraptraptr

3032.6e

41.1

38e

M1

M2

M3

aptraptraptr

48.74946.747.8

45.147.8

47.448

45.5

38.440e4948.3

30415 30638L 30638R

P1

P2

P3

aptraptraptr

26.217

39.93239.731.8

39e

P4

M1

aptraptr

3432.144.439

33.232.746.337.8

M2

M3

aptraptr

50.546.851.546.4

53.546.252.147.3

Hexaprotodon cf. Hex. protamphibius has beenrecognized from the Apak Member of the Nachu-kui Formation (Weston, 2003) and Hex. protam-phibius persists into the Kalochoro Member of theNachukui Formation (Harris et al., 1988). It is like-ly that Hex. protamphibius gave rise to Hex. ka-rumensis Coryndon, 1977, that dominated the lat-est Pliocene and early Pleistocene aquatic habitatsof the Lake Turkana Basin (Harris, 1991a), an in-terpretation supported by the phylogenetic analysisof Boisserie (2002).

Hexaprotodon sp. indet.(Figure 16; Table 22)

KANAPOI MATERIAL. 30552, Lt. max withP2–M3.

One maxilla has teeth that are appreciably small-er than the material attributed to Hexaprotodonprotamphibius but by itself is insufficient to deter-mine whether this is Hippopotamus imagunculusHopwod, 1926, the small hippo common to theWestern Rift, or a progenitor of Hexaprotodon ae-thiopicus (Coryndon and Coppens, 1975) the smallspecies present in Plio–Pleistocene horizons in thennorthern Turkana Basin, or an entirely new species.

Family Suidae

Genera of the suid subfamilies Hyotheriinae, Lis-triodontinae, and Sanitheriinae predominated inthe early and middle Miocene of sub-Saharan Af-rica but in the late Miocene were replaced by te-traconodontine immigrants from Asia. Nyanza-choerus Leakey, 1958, and the more hypsodontNotochoerus Broom, 1925, were characteristic te-traconodontine genera of the latest Miocene andearly Pliocene of sub-Saharan Africa. These twogenera persist into late Pliocene localities, wherethey are joined by a second wave of Asian immi-grants comprising the suine genera Kolpochoerusvan Hoepen and van Hoepen, 1932, Metridiocho-erus and Potamochoerus Gray, 1854. The lastthree genera are not present at Kanapoi.

Nyanzachoerus Leakey, 1958

Nyanzachoerus, as diagnosed by Cooke and Ewer,1972, and Harris and White, 1979, is a tetracon-odontine genus that evidently migrated to Africafrom Asia during the late Miocene. Nyanzachoerecheek teeth are similar to those of the extant Po-

tamochoerus in basic structure but tending to bemore hypsodont and with main cusps of molars dis-tinctly more columnar. The third and fourth pre-molars are relatively larger than in Potamochoerus.The upper canines are oval to flattened oval intransverse section, the lower canines verrucose withthin, weakly grooved enamel on two lateral faces.Strong sexual dimorphism is expressed by the size


Table 21 Kanapoi Hexaprotodon cf. H. protamphibiuslower teeth measurements

1 6R 6L 7 15

Ii

I2

I3

aptraptrap

2525.416.1

19.4

/C

P1

traptraptr

20e3858

P2

M1

M2

aptraptrap

33.4e

50.7

48.834.9

48.43655

46.733

M3

dP4

traptraptr

63e37e

43.970e37.3

24.8

27 30210 30211

P2

P3

P4

aptraptraptr

M1

M2

M3

aptraptraptr

46.535.4

62.737 34.5e

30599 30632 30638L 30638R 32521

Ii

I2

I3

aptraptraptr

20.621.4

272521.519.72321.7

27.525.5

/C

P1

P2

aptraptraptr

35.520.1

36.9e20

P3

P4

M1

aptraptrap 47

3723.138.92748

36.726.949.5

M2

M3

traptraptr

3552386436.9

34.951.536.563.535.8

50.535.7

of canines and massiveness of skull. Hollow bonyprotuberances or bosses are present on the zygo-matic arches in males but weak or absent in fe-males. The corpus of the mandible is heavy andcontrasts markedly with the unusually thin boneforming the angle.

Nyanzachoerus pattersoniCooke and Ewer, 1972

(Figures 17, 18; Tables 24–26)

KANAPOI MATERIAL. 201, Rt. P2–M3; 202,Rt. M3 broken; 205, Rt. M1 and M2; 206, partialRt. M2; 213, partial Lt. mand (Lt. P3–M2, M3 erupt-ing); 214, frag Lt. max (Lt. P3–4); 215, skeletal el-ements and tooth frags; 218, Rt. mandible frag(P3–4, M3 frag; 219, Rt. M2; 220, broken mand,teeth worn; 221, partial Lt. and Rt. mand rami(milk teeth and Rt. M1); 222, frag Rt. max (dP4,partial M1); 223, partial skull (Lt. P4, M3, Rt. M3);228, Rt. M1; 231, facial frag of old male; 232, Rt.M3 tooth frags; 238, Rt. M3; 239, female skull andmand (holotype); 240, Lt. and Rt. mand and teeth;244, subadult skull; 249, mand symph; 255, Lt.mand (Lt. P4–M2); 256, Rt. mand (P4–M3); 258,mand (Lt. P4–M3); 259, Lt. mand (M2 and M3);260, Rt. M2; 261, frag M3, C; 262, skull and mandfrags; 263, Lt. and Rt. mand (Lt. P3–M3); 264, bro-ken skull and mand (M3); 266, Lt. juv mand (C,dP2, M1–2); 273, M3; 275, Lt. mand (P4–M3); 329,female cranium and mandible, atlas vertebra, tho-racic vertebra; 533, mand frag (M3); 534, Lt. M3;18566, partial skull (Lt. P3–M2); 30159, Rt. P4 andM1 and tooth frags; 30160, female mand (Lt. andRt. I1–2, C, Rt. P2–M3); 30161, male mand (Rt. P4,M3, roots Lt. and Rt. I1-/C Rt. P2, P4–M1); 30162,male max (P2–4); 30165, male Lt. and Rt. C/, wornM frag, I2; 30166, Rt. mand (broken M3), Lt. P4,condyle, partial M3; 30168, Rt. mand (P2–3); 30177,female mand and symphysis (Lt. and Rt. I1–3, Lt.P2–3, M2–3, Rt. P2–4); 30179, mand (broken M2–3);30181, M3 lacking talonid; 30183, mand (M2–3),and frags symphysis; 30186, male cranium; 30203,male mand, skull and tooth frags; 30205, femalesymphysis (Lt. I1–2), Rt. P3, P4; 30267, Lt. and Rt.male mand and symphysis (Rt. /C–M3, Lt. P3–M3);30268, male broken max and premax (Lt. and Rt.M3); 30271, very broken male skull and teeth;30403, Rt. mand frag (M3 and roots M2); 30409,Lt. mandible (P4, roots M1, M2–3), tusk and mandfrag; 30410, mand and broken teeth and dist tibiafrag; 30411, M3 talonid; 30413, DP4 and M1 andbone frags; 30430, Lt. max (P4–M2); 30433, partialskull and teeth; 30453, Rt P3–4; 30456, M2; 30458,Lt. M2; 30462, Rt. M2; 30474, upper teeth (Rt. P4,partial M1, M2, M3); 30475, Lt. mand (P3–M2),tooth frags; 30543, molar frags; 30545, I3; 30547,Lt. mand (dP4, M1–2); 30551, Rt. mand frags (M3);30553, Lt. mand (P3–M2), Rt. mand (P3–M3) andfrags; 30615, P3; 30620, Male Rt. mand (P4–M3);32515, Rt. M3 and tooth frags; 32530, P2; 32539,Rt. mand (P4–M3); 32553, Rt. I2; 32802, mand (Rt.


Figure 16 KNM-KP 30552; Hexaprotodon sp. indet. left maxilla with P2–M3, occlusal view; scale 5 cm

Table 22 Kanapoi Hexaprotodon sp. upper teeth mea-surements

30552

P2

P3

P4

aptraptraptr

28.22

31252223.5

M1

M2

M3

aptraptraptr

343339.741.142.6

P3–M3); 36841, broken mand (partial P3, M1, M2,M3) and opp P; 38978, male mandible Rt. /C–M3,Lt. /C–P3.

Nyanzachoerus pattersoni is a sexually dimor-phic nyanzachoere that is larger than the late Mio-cene Ny. syrticus (Leonardi, 1952) from Lothagamand Sahabi. The first premolars are vestigial or ab-sent. The third and fourth premolars are robustcompared with those of Ny. syrticus subspecies butare relatively smaller, and the third molars are moreelongate and with a more complex talon (id) (Har-ris and White, 1979). M3 length is between 48 and60 mm (van der Made, 1999). The holotype is afemale skull from Kanapoi (KNM-KP 239).

Nyanzachoerus pattersoni is the common suid atKanapoi. Harris and White (1979) interpreted Ny.pattersoni as a junior synonym of Nyanzachoeruskanamensis Leakey, 1958, but we now consider Ny.kanamensis to be a species with narrow premolars

whose distribution was limited to the Western Rift(Harris and Leakey, 2003c). The teeth of Ny. pat-tersoni may be distinguished from those of Ny. syr-ticus and Ny. devauxi (Arambourg, 1968) by theirlarger size, more complex third molar talon(id)s,and proportionately smaller premolars. The thirdmolars are shorter and have less complex talon(id)sthan those formerly assigned to ‘‘Nyanzachoerus’’jaegeri Coppens, 1971.The teeth display consider-able size variation, polarizing between larger maleand smaller female specimens. The larger maleteeth are only slightly smaller than those of Ny. aus-tralis Cooke and Hendey, 1992, from Langebaan-weg, but we think the variation seen in the Kanapoisample reflects sexual dimorphism rather than thepresence of two dentally similar species.

The mandible of Nyanzachoerus pattersoni is ro-bustly constructed. The symphysis is relatively nar-row across the canine alveoli and moderately con-cave. The anterior border, which bears three pairsof well-developed and closely proximate incisors, isarched and projects in front of the canines. Theconcave superior symphysial surface is deeply ex-cavated in front of the posterior border. The rela-tively small but stout canines are set at an obliquerather vertical angle. The inferior surface is smoothand only slightly flattened toward the incisive al-veoli. The mandible constricts to its minimumwidth midway along the relatively short postcaninediastema. The posteroventral border mergessmoothly with the inferior body of the corpus,which is short, robust, and becomes graduallydeeper posteriorly.

At Lothagam, Nyanzachoerus syrticus and themuch smaller Ny. devauxi predominate in the Na-wata Formation. The more progressive Ny. patter-soni has not been recovered from strata earlier thanthe Kaiyumung Member although the dentally sim-


Figure 17 KNM-KP 30186, Nyanzachoerus pattersoni, cranium; A 5 left lateral view; B 5 dorsal view; C 5 anteriorview. Scale 5 5 cm

ilar but somewhat larger Ny. australis (Cooke andHendey, 1992) occurs in the Upper Nawata andApak Members.

Notochoerus Broom, 1925

Notochoerus species are tetraconodontines thathave wide and flat mandibular symphyses, smallpremolars, elongate molars, and very long and hyp-sodont third molars. The M3 is the longest of alltetraconodontines (van der Made, 1999).

Notochoerus jaegeri (Coppens, 1971)(Figures 19, 20; Tables 24, 27, 28)

KANAPOI MATERIAL. 203, C/ frag; 225, bro-ken Rt. M3 and partial Lt. M3; 209, partial M3;210, frag Rt. mand (M3 broken); 211, Lt. M3; 226,damaged mand (broken Rt. M3 and P3); 234, Lt.M3, frag Rt. M3; 235, mand (Lt. M3, broken Rt. P4

and /C); 241, damaged mandible (Rt. P3); 242,male skull frags (zygomatic knob); 245, partial M3;251, partial skull and mand; 252, upper female ca-nines; 253, Lt. M3; 254, Rt. M3 and tooth frags;257, partial skull (Lt. and Rt. P3–M3); 265, M3


Figure 17 Continued

frags; 267, mand; 269, juv mand (dP3–4, M1); 270,Lt. M3; 26944, Rt. M3 and tooth frags; 30178,large mand (Lt. /C, Rt. I1–3, Lt. and Rt. P3–M3);30180, Lt. mand (P3–M3); 30182, Lt. M2, Rt. M2;30185, tusk frags; 30402, mand (M2–3); 30452,mand (Rt. and Lt. /C–M3); 30484, M3 talon;30550, mand (M2–3); 30617, male skull (Rt. P3–M3); 32528, M1–3; 32801, Lt. mand. frag (M3).

Notochoerus jaegeri is a large progressive tetra-conodontine possessing three pairs of premolars, ofwhich the third and fourth are proportionatelysmaller than Ny. syrticus or Ny. pattersoni. Thethird molar is longer and taller and has more pillarsthan those of either of the latter taxa. There is atendency for the molar enamel to be folded. The

cranium and mandible are larger and more elongatethan in Nyanzachoerus species; strong sexual di-morphism is evident, with the zygomatic swellingsmore localized but more protuberant in males (afterHarris and White, 1979).

Cooke and Ewer (1972) assigned cranial anddental material of a large suid from Kanapoi andLothagam to their new species Nyanzachoerus pli-catus, but this taxon proved to be a junior synonymof the species Nyanzachoerus jaegeri erected byCoppens in 1971 for suid dentitions from Chad.Known mainly from its teeth, this species was in-terpreted by Harris and White (1979) to be mor-phologically and phylogeneticaly intermediate be-tween, on one hand, nyanzachoeres represented by


Figu

re18

KN

M-K

P23

9,N

yanz

acho

erus

patt

erso

ni,m

andi

ble;

A5

righ

tla

tera

lvie

w;B

5oc

clus

alvi

ew;s

cale

s5

5cm


Figure 19 KNM-KP 30617, Notochoerus jaegeri, cranium; A 5 dorsal view; B 5 occlusal view; scales 5 5 cm

Ny. kanamensis and Ny. pattersoni and, on the oth-er, the somewhat younger notochoeres representedby Notochoerus capensis Broom, 1925, from SouthAfrica and Not. euilus (Hopwood, 1926), fromeastern Africa. New mandibles recovered fromKanapoi by National Museums of Kenya expedi-tions have augmented our understanding of thisspecies and clarified its phylogenetic relationships.

In contrast with the relatively narrow mandibu-lar symphyses of Ny. pattersoni and Ny. syrticus,that of Notochoerus jaegeri resembles the mandib-ular symphysis of Notochoerus euilus in its breadthand flatness. The corpus of the Not. jaegeri man-

dible is longer and less robustly constructed thanthat of either Ny. pattersoni or Ny. syrticus. Thesymphysis is distinctly spatulate and flattened at thewidest point across the canine alveoli. The anteriorborder, which carries three pairs of rather small butwell-spaced incisors is almost straight and thick-ened ventrally at the alveolus. It projects onlyslightly in front of the anterior edges of the caninealveoli. Behind the canines, the superior surface isless deeply excavated. The large heavy canines ex-tend laterally and anteriorly from their alveoli at amore horizontal angle, curving posteriorly in theirdistal portions. The inferior surface thins anteriorly


Figure 20 Notochoerus jaegeri, mandibles; A 5 KNM-KP 30178, occlusal view; B 5 KNM-KP 30452, occlusal view;scales 5 5 cm


Table 24 Kanapoi Suidae mandible measurements

Nyanzachoerus mandibles

N. pattersoni M220

N. pattersoni239

N. pattersoni30161

N. pattersoni30410

N. pattersoni38978

Length symphysisWidth at caninesWidth at I3

Length P3–M3

Length P3–4

Min width diastema

1441

7615348.373

1187561

13844.655

12477.762

149.651.852.8

126

15748.660.2

14011101781

1454463

Notochoerus mandibles

N. euilus MER3540

N. euilus FKP30184

N. jaegeri MKP226

N. jaegeri MKP30178

N. jaegeri MKP30452

Length symphysisWidth at caninesWidth at I3

Length P3–M3

Length P3–4

Min width diastema

17216485

1593663

1311031

1734468

189178120.4

78

195150.588.6

18046.785

185114882

16345.274

Table 23 Kanapoi Suidae cranial measurements

Nyanzachoerus pattersoni 30186 M Notochoerus jaegeri 30617

Width canine flangesWidth canine alveoliNasal boss widthBizygomatic width

13616070

400

110.3

Width postorbital processesMax width occiputNuchal crest-foramen magnumBicondylar width

14013618576

133198.5

toward the incisor alveoli and between this and thecanines is shallowly excavated either side of themidline. The posteroventral border projects belowthe inferior surface of the corpus. Posterior to thecanines, the mandible constricts to its minimumwidth midway along the rather long postcanine di-astema. The corpus is long, narrow, and relativelylightly built. The inferior surface is elevated be-tween the posterior edge of the symphysis and theangle of the ramus.

The teeth of Not. jaegeri resemble a progressiveversion of Ny. kanamensis and Ny. australis teeth:the premolars have similar morphology but areproportionately smaller, the molars have similarmorphology but the talon(id) of the third molar ismore complex. However, the similarity of the ori-entation of the lower canines and the mandibularmorphology to that of Not. euilus argues for in-corporation of this species in Notochoerus ratherthan Nyanzachoerus.

Harris and White (1979) noted tetraconodontineupper third molars from Laetoli that they inter-

preted as primitive for Not. euilus on account oftheir larger size and more massive appearance. Re-comparison of the Laetoli suids with those fromKanapoi suggests that the massive upper molarsfrom Laetoli are better attributed to Not. jaegerithan to Not. euilus. Notochoerus jaegeri is also pre-sent in the Apak Member at Lothagam (Harris andLeakey, 2003c).

Notochoerus euilus (Hopwood, 1926)

Notochoerus euilus is a species of Notochoeruswith a deep and narrow cranium bearing sexuallydimorphic zygomatic knobs. The M3 has twostrong lingual talon pillars. The M3 typically hasthree pairs of talonid pillars plus single midline ter-minal pillar or series of pillars. Individual majorlateral pillars of molars are moderately tall, widelyseparated from adjacent lateral pillars, and tapersharply from their bases (Harris and White, 1979).


Table 25 Kanapoi Nyanzachoerus pattersoni upper toothmeasurements

201R 205R 205L 222R 223L

P2

P3

P4

aptraptraptr

23.8519.13

19.9722.31

M1

M2

M3

aptraptraptr

28.69

49.7129.62

16.9930.9324.27

16.7

49.9933.69

dP3

dP4

aptraptr

12.7819.6214.47

12.3415.8218.01

239L 239R 244L 244R 260

I1

I2

I3

aptraptrmd

18.811.617.88.4

C/

P1

P2

aptraptraptr

25.816.4

127.1

22.217

7.37

12.367.65

P3

P4

M1

aptraptraptr

20.519.418.821.618e

21.918.917.720.620e

19.3124.492020.9

20.2425.9322.5220.84

M2

M3

aptraptr

26.725.346.634

242547.633.6

32.0124.68

30.6425.6

27.920.4

264L 18566L 30159R 30162R

P2

P3

P4

aptraptraptr

19.1720.2223.45

18.322.5

10.036.5

21.8918.4817.4721.7

M1

M2

M3

aptraptraptr

50.7231.24e

17.98

28.5128.51

18.3e19.5e

Table 25 Continued

30177 30177L 30177R 30268L 30268L

C/ aptr

26.515.4

P1

P2

aptraptr

P3

P4

M1

aptraptraptr

22.2721.5318.5121.96

22.5422.5618.9123.221.0817.62

M2

M3

aptraptr

51.89 51.5e

30268R 30413 30433L 30433R 30453R

P2

P3

P4

aptraptraptr

12.17.9

2221.51923.7

22.320.718.424.3

23.7

18.723.2

M1

M2

M3

aptraptraptr

47.69

21.819.9

15.7e20.726e24

31.4

15.7e18.4e27.427.7

28.9

30474 30615 32515 30474R

P3

P4

M1

aptraptraptr

22.1

22.7

19.916.3

M2

M3

aptraptr

24.924.848.4 48.2

31.4

25.4324.9149.07

Notochoerus cf. Not. euilus(Figure 21; Tables 24, 29)

KANAPOI MATERIAL. 30184, female mandwith symphysis (Rt. P4–M3, roots Lt. and Rt. I1, /C).

One mandible, female from the size of its ca-nines, has a third molar that terminates in a com-plex of pillars rather than in a fourth pair of pillars,thereby resembling the third molar of Not. euilus.The incisors and premolars are small but not asreduced as those of Not. euilus from the LokochotMember at Koobi Fora (Harris, 1983b). At Loth-agam, Notochoerus euilis is the predominant suid


Figure 21 KNM-KP 30184, Notochoerus cf. N. euilus mandible; A 5 right lateral view; B 5 occlusal view; scales 5 5cm

in the Kaiyumung Member but there is a caninefrom the Apak Member that may also belong tothat species.

Family Giraffidae

Giraffoids are rare elements of middle Miocene fau-nas in East Africa, being best represented by Cli-macoceras africanus MacInnes, 1936, at Maboko,Climacoceras gentryi Hamilton, 1978, at Fort Ter-nan, and Palaeotragus primaevus Churcher, 1970,from Fort Ternan and Ngorora (Hamilton, 1978).Palaeotragus germaini, first described from lateMiocene localities in North Africa (Arambourg,1959), has been reported from Lothagam (Church-er, 1979), as has a second smaller Palaeotragus,species (Harris, 2003a). Palaeotragines are notfound at African Pliocene localities, their place be-

ing taken by more derived sivatheriines (Sivather-ium Falconer and Cautley, 1832) and giraffines(Giraffa Brunnich, 1771), both probably being de-rived from Eurasia immigrant stock (Harris,2003a).

Giraffa Brunnich, 1771

Giraffa stillei (Dietrich, 1942)(Table 30)

KANAPOI MATERIAL. 30151, Rt. M2 or 3;30428, Rt. P4 and M1; 30635, Lt. P2; 30636, Rt.M1or2; 30637, upper tooth frags.

Giraffa stillei is a small species of Giraffa withteeth that are often smaller than those of G. ca-melopardalis (Linnaeus, 1798) and G. jumae Lea-key, 1965, but always larger than those of G. pyg-


Table 26 Kanapoi Nyanzachoerus pattersoni lower teeth measurements

202R 213L 215 219R 220R

P2

P3

P4

aptraptraptr

24.5619.4721.7819.5

22.11

10.877.55

28.3122.2824.4822.75

M1

M2

M3

aptraptraptr 24.04

52.8825.19

27.7921.6949.7725.21

28.6822.78

28.85

56.6128.61

221R 228 228L 236L 239L

I1

I2

I3

aptraptraptr

8.91212.314.610.210

/C

P1

P2

aptraptraptr

19.913.2

10.96.6

P3

P4

M1

aptraptraptr

21.7913.62

1913.9

27.5224.4626.38

20.45

16.8e

M2

M3

aptraptr

32.1625.99

31.41 23.7

52.823

239R 240L 240R 255L 256R 258L

I1

I2

I3

aptraptraptr

8.711.710.913.410.68.7

/C

P1

P2

aptraptraptr

21.513.4

116.7

P3

P4

M1

aptraptraptr

22.817

22.7419.88

M2

M3

aptraptr

53.322.9

27.2719.81

26.4620.4554.6224.05

26.7320.8

53.8723.781

27.4121.1160.1725.32


Table 26 Continued

259L 260R 260R 262L 263L 264L

P2

P3

P4

aptraptraptr

23.2619.7820.6119.4

11.267.78

26.6220.6923.7121.58

M1

M2

M3

aptraptraptr

54.21

19.8713.64

19.2114.525.9820.1448.7922.53

33.7325.8

19.513.1826.1918.06

27.64

56.3228.86

266L 533R 534L 30160 30161

I1

I2

I3

aptraptraptr

13.415.612.417.4

/C

P1

P2

aptraptraptr

22.815.3

8.27.5

P3

P4

M1

aptraptraptr

27.320.924.421.3

24.717.5

M2

M3

aptraptr

24.6419.39

25.656.4826.72

26.422.7e50.626.4

49.225.6

30161R 30168R 30177L 30177R 30177R 30179L

I1

I2

I3

aptraptraptr

13.4e10.914.713.88.6

12.5/C

P1

P2

aptraptraptr

9.088.25

9.857.78

P3

P4

M1

aptraptraptr

20.716.3

24.417.5

25.2321.36

25.7119.51

M2

M3

aptraptr

24.319.752.9e24.1

48.4325.65

75.67e


Table 26 Continued

30183L 30205R 30267L 30267R 30267L

I1

I2

P2

aptraptraptr

9.977.81

9.112e12e13.6e8.77.42

P3

P4

M1

aptraptraptr

25.6119.7522.4720.34

27.4521.0322.521.33

24.8418.2721.7818.51

23.5618.3121.2220.0617.83

25.318.2222018

M2

M3

aptraptr

54.3424.23

26.0923.52E52.1627.64

28.121.3154.0625.26

28.521.554.824.9

30267R 30403 30409 30410L 30410R 30456

/C

P1

P2

aptraptraptr

32.322.9

107.1

P3

P4

M1

aptraptraptr

25.318.522.219.519.215.5

2319

25.017.523.520.9e20.8e

25.518.722.020.5

M2

M3

aptraptr

28.52254.524e

50.7e23.3

2619.250e22.6

55.6e

2617.1

30458L 30458 30462 30475 30475L 30545

I3

/C

P1

aptraptraptr

10.18.5

P2

P3

P4

aptraptraptr

10.327.12

22.9118.2921.4519.64

26.624.426.2e

M1

M2

M3

aptraptraptr

18.0614.8827.421.2654.4323.94

28.920.8

2921.5e

3326

30.2419.87


Table 26 Continued

30620 32539 32553

I3 aptr

13.715.5

/C

P1

aptraptr

P2 aptr

P3

P4

aptraptr

23.220.3

21.219.1

M1

M2

M3

aptraptraptr

19.515.627.421.858.7e

18.114.6e2519.75024.3

maea Harris, 1976. The ossicones are uprightly in-serted like those of G. camelopardalis but appre-ciably smaller than male specimens of the extantspecies and often lack well-developed terminalknobs; they are larger than specimens assigned toG. pygmaea but are not backwardly raked likethose of G. jumae.

Five isolated teeth attributed to G. stillei aresmaller than those of extant giraffes except for oneanterior lower premolar (KP 30365) that is aboutthe same size as that of the extant species.

Giraffa jumae Leakey, 1965(Table 31)

KANAPOI MATERIAL. 30450, Lt. mandible(P2–M3).

Giraffa jumae is a large species of giraffe of sim-ilar size to the extant G. camelopardalis. The sur-face of the frontal bone between the external rimsof the orbits is nearly flat. The width of the skullroof between the orbits is greater than in G. ca-melopardalis. The longitudinal median sectionfrom the posterior edge of the nasals to the lateralossicone is flat or slightly concave. The lateral os-sicones originate immediately above the orbit andproject more posteriorly than in G. camelopardalis.No secondary bone apposition is known to occuron the lateral ossicones. The median ossicone ispoorly developed. The basilar process of the occip-ital is longer than the external width of the palatalarea at M2. The ascending ramus of the mandibleis wide and stout. The corpus is deep and long, theanterior portion of the corpus being inclined up-ward from the premolars to the symphysis and thendownward in the incisive region.

Only one mandible of G. jumae has been recov-ered from Kanapoi. The lower teeth are somewhat

larger than those of extant giraffes and the anteriorpremolar (P2) is significantly larger.

Giraffa sp. indet.(Table 32)

KANAPOI MATERIAL. 98, distal metacarpal;480, prox phalanx; 472, Lt. astragalus; 473, Rt.astragalus frag; 30446, prox metacarpal; 42091,Lt. radioulna; 42092, Lt. radioulna, Lt. metacarpal,Lt. cuneiform, Lt. semilunar; 42093, Lt. tibia andRt. humerus.

None of the postcranials were found in associa-tion with teeth or ossicones. All are somewhatsmaller than those of extant giraffes and thus aremore likely to represent Giraffa stillei rather thanG. jumae.

Sivatherium Falconer and Cautley, 1832

Sivatherium hendeyi Harris, 1976

Sivatherium hendeyi is of similar size and dentalmorphology as the Asian S. giganteum Falconerand Cautley, 1832, and the later African species S.maurusium Pomel, 1892, but the posterior ossico-nes are short, extending laterally and backwardfrom the cranium, and are unornamented by knobsor flanges or palmate digitations. The metacarpalslonger than in S. giganteum or in Pleistocene spec-imens of S. maurusium (after Harris, 1976b).

Sivatherium cf. S. hendeyi(Table 33)

KANAPOI MATERIAL. 135, Lt. fibula; 30227,upper and lower molar frags; 30449, prox Rt. os-sicone frag; 32551, Rt. M/ and Rt. M3 frags.

The proximal right ossicone fragment is trian-


Table 27 Kanapoi Notochoerus jaegeri upper teeth

211L 225L 225R 234L

P2

P3

P4

aptraptraptr

23.0120.03E15.8619.21

11.487.15

22.4919.0719.0521.83

11.377.42

21.1219.4318.3821.89

M1

M2

M3

aptraptraptr

25.5626.3947.2233.45

23.9524.3649.3733.68

66.89e32.59e

dP3

dP4

aptraptr

253R 257L 257R 26944 26944L

P2

P3

P4

aptraptraptr

21.8319.4218.7620.98

24.1518.3916.3921.37

M1

M2

M3

aptraptraptr

71.7833.23

30.8625.1463.8235.46

29.7925.7163.7736

71.236.8

72.3136.99

30617L 30617R

P2

P3

P4

aptraptraptr

22.3e20.8

23.021.0

M1

M2

M3

aptraptraptr

35.825.974.035e

27e74.236.9

gular in transverse section with convex anterome-dial and anterolateral surfaces and a flattened pos-terior surface. The ossicone has a basal sinus andis massive proximally but tapers above the base.The ossicone is somewhat bovine in appearanceand appears to have extended outward and back-ward at the base but curves medially. The anteriorsurfaces are marked with deep longitudinalgrooves. Compared with ossicones of S. mauru-sium, this specimen is smaller, more gracile, andlacks the lateral bosses. Compared with the horn

cores of the bovin Simatherium Dietrich, 1941, theossicone lacks the strong dorso-ventral compres-sion of the bovin horn core and tapers less gradu-ally distally.

The giraffid tooth fragments assigned to Sivath-erium are much larger than the teeth in the G. ju-mae mandible.

Harris (1976b) proposed the name S. hendeyi forthe Langebaanweg sivatheres, which were charac-terized by ossicones that were shorter and simplerthan those of S. maurusium from younger sites.Churcher (1978) did not use this name but thoughtthe Langebaanweg sivatheres may represent an an-cestral African sivathere population. We now knowthat Pliocene sivathere metapodials associated withS. maurusium ossicones were originally of similarlength to those of S. hendeyi but underwent a dra-matic reduction in length when S. maurusiumadopted a grazing diet at the end of the Pliocene(Harris and Cerling, 1998; Cerling et al., in press).The Kanapoi ossicone is referred to S. hendeyi onthe basis of its size and morphology.

Family Bovidae

The family Bovidae is sparsely represented at earlyMiocene localities in East and North Africa (Ham-ilton, 1973; Gentry, 1978) but bovids were themost numerous terrestrial mammals at the mid-Miocene site of Fort Ternan (Gentry, 1970) andthey dominate younger vertebrate fossil assemblag-es from eastern Africa. Bovids occur in both Eur-asia and Africa during the early Miocene, andthereafter, migrations occurred between them re-peatedly (Vrba, 1985, 1995) but Gentry (1990) ar-gues for Africa as the origin of this family. Becausethe sole apomorphic character characterizing thefamily Bovidae is the presence of horn cores (Janisand Scott, 1987), it would be difficult to substan-tiate a hornless bovid ancestor with any degree ofcertainty.

The Antilopini and Caprini, both of Eurasian or-igin, are first represented in Africa about 14 millionyears ago; the endemic Cephalophini and Neotra-gini make their appearance shortly thereafter. To-ward the end of the Miocene, Ovibovini and Bovinimigrated into Africa from Eurasia while the endem-ic Tragelaphini, Hippotragini, Alcelaphini, and Ae-pycerotini are documented for the first time. TheReduncini, whose continent of origin is uncertain,also appear in the late Miocene whereas the Bose-laphini become extinct in Africa near the Mio–Pli-ocene boundary (Vrba, 1985).

The Kanapoi bovid assemblage is dominated bytragelaphins, alcelaphins, and aepycerotins—sug-gesting a mixture of open and closed mesic to xerichabitats. Boselaphins, common elements in the Na-wata Formation at Lothagam and persisting intothe Apak Member (Harris, 2003b), have yet to berecovered from Kanapoi.


Table 28 Kanapoi Notochoerus jaegeri lower teeth mea-surements

210R 226 235R 235L

P2

P3

P4

aptraptraptr

13.421

M1

M2

M3

aptraptraptr

80.5627.89

67.6627.06

241R 267R 251L 251R 252R

P2

P3

P4

aptraptraptr

23.8616.71

22.5513.7418.115.32

23.9716.8419.8917.18

22.4816.78

M1

M2

M3

aptraptraptr

64.5525

61.1825.07

20.4413.81

267L 269R 30178L 30178R

P2

P3

P4

aptraptraptr

25.8517.9220.8818.48

25.5517

17.8eM1

M2

M3

aptraptraptr

81.9728.37

26.614.05

34.0623.5577.2830.34

35.7924.65e80.8730.37

30180L 30182L 30402 30550 32258

P2

P3

P4

M1

aptraptraptraptr

23.616.419.717.1

16M2

M3

aptraptr

3122e70.224.9

3220.21 22.3

76.630.3

82291

35.623.678.929.6

Table 28 Continued

32801 30180L 30182R 30452R 30452L

P2

P3

aptraptr

23.6216.49

26.6117.64

26.48

P4 aptr

19.4717.11

20.68 20.46

M1

M2

M3

aptraptraptr

19.415

76e26e

31.78

71.9925.04

35.5119.95 21.22

71.6523.8

29.18

71.5124.7e

Table 29 Kanapoi Notochoerus euilus lower tooth mea-surements

30184R

I2

P2

P3

mdblaptraptr

11.713.6

P4

M1

aptraptr

20.516.721.014.9

M2

M3

aptraptr

32.421.473.525.8

Tribe Tragelaphini

Tragelaphus Blainville, 1816

Tragelaphus species are medium to large tragela-phins with spiraled horn cores inserted close to-gether and having an anterior keel and sometimesa stronger posterolateral one; small- to medium-sized supraorbital pits, which are frequently longand narrow, and an occipital surface tending tohave a flat top edge and straight sides (Gentry,1985). The genus Tragelaphus is diverse, includingthe kudus, the nyalas, the sitatunga, and the moreubiquitous bushbuck. Greater and lesser kudus oc-cur today in the northern half of the Turkana Basin.

Tragelaphus kyaloae Harris, 1991(Table 34)

KANAPOI MATERIAL. 68, occiput; 77, Lt. h/cfrags; 78, Lt. h/c frag; 79, Rt. and Lt. h/c frags; 80,Lt. h/c frag; 81, Rt. h/c frags; 82, Rt. h/c frags; 84,dist Rt. h/c frag; 86, Lt. h/c frags; 87, dist Lt. h/c;88, dist. Rt. h/c frag; 89, dist. Rt. h/c frag; 90, prox


Table 30 Kanapoi Giraffa stillei tooth measurements

KP 30635 KP 30636 KP 30637A KP 30637B KP 30428 30151

P/

M/

aptrapprotmet

25.4125.37

18.5116.4321.221 23.16

24.4521.65

P2

P3

P4

aptraptraptr

15.2510.61

M1

M2

approtmetapprotmet

23.7416.4716.64

M3 approtmet

Table 31 Kanapoi Giraffa jumae tooth measurements

KP 30450

P2

P3

P4

aptraptraptr

20.6213.62125.0319.8326.1522.17

M1

M2

approtmetapprotmet

28.81

29.7622.5222.62

M3 approtmet

46.4223.8921.56

Rt. h/c frag; 91, prox Lt. h/c frag; 92, frontlet andprox Rt. h/c; 29258, prox Rt. h/c frag; 29260, proxRt. h/c; 29261, prox Rt. h/c; 29268, prox Rt. h/c;29269, dist Rt. h/c; 29272, prox Lt. h/c; 29278,dist Rt. h/c; 30156, h/cs and frontlet; 30158, cal-varia and h/cs; 30445, prox Rt. h/c; 30448, h/cfrags; 30486, dist. Rt. h/c; 30628, dist Lt. h/c frag;30629, Rt. h/c frag; 30634, prox Lt. h/c; 32519,prox Rt. h/c frag; 32559, dist. Rt. h/c frag; 29266,dist Lt. h/c.

Tragelaphus kyaloae is a medium-sized tragela-phin with horn cores inserted close together, at alow inclination, that diverge rapidly from their basebut converge distally, and that spiral 1808 anti-

clockwise in the right horn core. Proximally, thereis a strong posterolateral keel and a fainter antero-lateral keel; distally, these become anterolateral andposteromedial, respectively. The shape of the horncores is reminiscent of the extant sitatunga (T. spek-ei Sclater, 1863); they are less helically coiled thanin T. strepsiceros (Pallas, 1766), T. imberbis Blyth,1869, or T. gaudreyi (Thomas, 1884) but convergecloser distally than in T. nakuae Arambourg, 1941,or the kudu-like species. The cranial vault bears afaint but distinct transverse bar immediately infront of the nuchal crest. The paroccipital processesare short but stout, and the posterior tuberositiesof the basioccipital are much wider than the ante-rior ones.

This is by far the most abundant bovid in theKanapoi biota. The holotype of T. kyaloae is fromthe lower Lokochot Member at Kosia (Harris,1991b) and it is the common tragelaphin in the Lo-kochot and Moiti Members of the Koobi Fora For-mation (Harris, 2003b). The oldest documented oc-currence of this taxon is a single specimen from theUpper Nawata at Lothagam but it is also repre-sented by a dozen horn cores from the Apak andKaiyumung Members of the Nachukui Formationat Lothagam. The horn cores are similar in cross-section to those of T. nakuae, the common Pliocenetragelaphin of the Lake Turkana Basin, but havemore pronounced torsion.

Tragelaphini gen. indet.(Table 35)

KANAPOI MATERIAL. 32514, Lt. maxilla (P4–M3); 66, Rt. mandible (M2–3); 67, Lt. mandible frag(M1); 76, Lt. M1; 109, Lt. M1; 29273, Lt. and Rt.


Table 32 Kanapoi Giraffa sp. indet. postcranial measurements

Specimen Length Prox ap Prox tr Dist ap Dist tr Epic tr

420934209242092

98

HumerusRadiusProx ulnaMetacarpal

70.43 115.1463.31

119.566.48

61.8

110.42106.77

92.15

125.58

304464209242093

480

MetacarpalMetacarpalTibiaProximal phalanx 66.98

37.4366.7

33.2

65.0197.7

33.15

57.6376.5922.48

86.53102.9527.86

Max ap Max tr Max dv

4209242092

CuneiformSemilunar

69.561.4

35.043.5

60.548.0

Table 33 Kanapoi Sivatherium fibula measurements

Length Prox tr Dv

135 55.79 31.42 33.85

M1–2; 30395, Lt. M1–2; 30396, Lt. M3; 30421, Rt.M1, Lt. M2, Rt. M3; 30441, Lt. M1; 32545, Lt.mandible frags (P2–M1); 32570, Lt. mandible frags,P3–M1; 32573, M/, Lt. M1, and tooth frags; 32574,Lt. M1; 32829, upper and lower molar frags;32881, Rt. P3; 36861, Rt. mandible (P3–4) and bonefrags.

A number of isolated tragelaphin dentitions wererecovered. Most are of similar size and presumablyrepresent Tragelaphus kyaloae but the smaller KP32514 indicates that at least two tragelaphin spe-cies were present at Kanapoi.

Tribe Bovini

Simatherium Dietrich, 1941Only one extant bovin species, Syncerus caffer(Sparrman, 1779), is endemic to sub-Saharan Af-rica but three other genera—Ugandax Cooke &Corydon, 1970, Simatherium, and Pelorovis Reck,1928—are represented in the fossil record. Simath-erium differs from Ugandax by being larger andhaving more widely separated horn cores that aremore divergent basally and more curved anteriorly.The more derived Pelorovis, is unknown before thelate Pliocene. Simatherium kohllarseni Dietrich1942 was originally described from Laetoli in Tan-zania whereas the somewhat older Simatherium de-missum Gentry, 1980, was first described from Lan-gebaanweg in South Africa.

Simatherium demissum Gentry, 1980

Simatherium cf. S. demissum(Figures 22, 23; Tables 36, 37)

KANAPOI MATERIAL. 96, Rt. mandible (P2–M3) and assoc postcranial; 29265, skull frags, Lt.

maxilla (P2–M3), Rt. maxilla (P4, M2–3); 30612,broken skull with Rt. and Lt. h/cs; 32560, Lt. M1

frag.This Kanapoi bovin is represented by a very bat-

tered calvaria with portions of both horn cores andby a partial upper dentition, both collected by Na-tional Museums of Kenya parties, and by a man-dible and associated postcranial elements that werecollected by the Harvard University expedition.The horn cores are strongly dorso-ventrally com-pressed. They extend outward and backward fromtheir bases but ascend upward toward their tips.The horn cores taper gently in their proximal por-tion but more rapidly toward their tip. The surfaceof the horn cores is not well enough preserved toconfirm the presence or absence of a lateral keelbut are otherwise ornamented by strong longitudi-nal ridges and furrows. Although the bone is veryincompletely preserved, the braincase evidently ex-tended for some distance behind the horn cores andwas bordered by well-developed temporal fossae.There was a strong interfrontal crest.

Tribe HippotraginiThere are three extant genera of hippotragins—Hippotragus Sundevall, 1846 (roan and sable an-telopes), Oryx Blainville, 1816, and Addax Rafin-esque, 1815, and several extinct genera. Vrba(1987) suggested that, early in their history, the hip-potragins diverged into two major subclades—oneexemplified by Hippotragus, with uprightly insert-ed and mediolaterally compressed horn cores, andthe other by the less water-dependent Oryx and Ad-dax, with horn cores that are less mediolaterallycompressed but bent more strongly backwards.

Hippotragini gen. indet.(Figure 24; Table 38)

KANAPOI MATERIAL. 483, B–D, Lt. P4–M1,Lt. M3, Rt. M2; 29274, Rt. mandible (M2–3); 30631,proximal Rt. h/c; 32526, Lt. M1.

This taxon is represented by the proximal por-tion of a large right horn core that is mediolaterally


Figu

re22

KN

M-K

P30

612,

Sim

athe

rium

cf.

S.de

mis

sum

,cal

vari

a,do

rsal

view

;sca

le5

5cm


Figure 23 Simatherium cf. S. demissum, dentitions; A 5 KNM-KP 29265, left maxilla, dorsal view; B 5 KNM-KP 96,right mandible (P3–M3), lateral view; C 5 KNM-KP 96, occlusal view; scales 5 5 cm

compressed with a flattened lateral surface. Thehorn core curves gently backward from its basewith a slight lyrate flexure in anterior view. Thereis faint transverse annulation on the anterior sur-face. At its base, the horn core measures 46.1 mmanteroposteriorly; the transverse measurement is33.9 mm.

A few hippotragin teeth were recovered although

none were associated with the sole recognized hip-potragin horn core.

Tribe RedunciniReduncins are small to large antelopes with hyp-sodont teeth for grazing and today characteristical-ly occur in grasslands near permanent water. Thereare two extant genera—Kobus Smith, 1840 (water-


Figure 24 KNM-KP 30361, Hippotragini gen. indet., proximal right horn core; A 5 lateral view; B 5 medial view;scales 5 5 cm


Table 34 Kanapoi Tragelaphus kyaloae horn core measurements

prox ap (Rt) prox tr (Rt) lt (Rt) prox ap (Lt) prox tr (Lt) lt (Lt)

7778798081

41

311

50

3838

33

53.12150

44

86909192

29258

37

3838

45

4649

33

43

47

56

29260292612926829272

4037

5348

3938

5146

30156301583044530634

38423834

50545352

3841

4955

bucks, kobs, etc.) and Redunca Smith, 1827 (reed-bucks). The earliest recognized species of Kobus arefrom Lukeino and Lothagam.

Kobus Smith, 1840

Kobus sp. indet.

KANAPOI MATERIAL. 461, Rt. h/c frags;29267, proximal Rt. h/c.

KP 29267 is a small but stout horn core thatcurves backward and slightly outward from itsbase. The horn core tapers gently upward from itsbase and the lateral surface is slightly flattened. Atits base, KP 29267 measures 35.5 mm anteropos-teriorly and 28.2 mm transversely. Correspondingmeasurements for KP 461 are 34.9 and 28.8 mm.The two horn cores are smaller than those of K.presigmoidalis Harris, 2003b, from Lothagam.

Reduncini gen. indet.(Table 39)

KANAPOI MATERIAL. 75, Rt. P3; 463, Lt.mandible (M1); 29275, Rt. maxilla (P4–M3); 29276,Rt. mandible (P2–M1); 29279, Rt. mandible (P2,M1–3); 30626, Lt. mandible (P4–M1); 27450, Lt.M1.

A few reduncin teeth were recovered but nonewere associated with the Kobus horn core.

Tribe Alcelaphini

Alcelaphins are represented by four extant genera:Damaliscus Sclater and Thomas, 1894, BeatragusHeller, 1912, Alcelaphus de Blainville, 1816, andConnochaetes Lichtenstein, 1814, plus a number ofextinct genera. All the extant genera are specialistbulk grazers that are capable of going without wa-ter for varying intervals of time. Damalacra species

were originally described from Langebaanweg(Gentry, 1980) and the genus was subsequently rec-ognized at Lothagam (Harris, 2003b) and else-where. A cladistic analysis of fossil and living Al-celaphini by Vrba (1997) suggested that two alce-laphin subtribes diverged during or before the Mio–Pliocene transition—the Alcelaphina (Damalacraneanica Gentry, 1980, and Beatragus) and the largeclade Damalascina (which includes the Damaliscusand Parmularius Hopwood, 1934 lineages). Bothsubtribes appear to be represented at Kanapoi.

Damalacra Gentry, 1980

Damalacra neanica Gentry, 1980Horn cores of Damalacra neanica are without com-pression or are slightly compressed anteroposteri-orly, have no flattened lateral surface, taper fairlysharply from base to tip, show much increased di-vergence distally, have either slight forward orslight backward curvature in profile, and are in-serted behind or above the back of the orbits. Theboundary between the pedicel top and the base ofthe horn core is higher on the medial than on thelateral side of the horn cores. Female horn coresare smaller than those of males, as in extant alce-laphins (after Gentry, 1980).

Damalacra cf. D. neanica(Figure 25)

KANAPOI MATERIAL. 71, frontlet with Rt.and Lt. h/cs.

The sole specimen comprises a frontlet withproximal horn cores that have long pedicels hol-lowed out by very large basal sinuses. The horncores diverge outward and taper rapidly upwardfrom their bases. They are ornamented by stronglongitudinal ridges and furrows. The face was evi-


Figure 25 KNM-KP 71, Damalacra cf. D. neanica frontlet with proximal horn cores; A 5 anterior view; B 5 rightlateral view; scales 5 5 cm


Table 35 Kanapoi Tragelaphini dentition measurements

109 29273L 29273R 30395 32514

P4

M1

aptraptr

23.016.9

21.215.9

21.515.4

18.923.0

10.314.413.814.2

M2

M3

aptraptr

21.816.6

22.817.0

27.824.0

18.117.821.716.2

30396 30441

M1

M2

M3

aptraptraptr

26.114.4

19.716.5

66 67 32574 32881 32570

P3

P4

M1

aptraptraptr

17.610.2

11.97.4

12.98.0

14.48.9

15.910.8

M2

M3

aptraptr

19.013.029.912.7

18.9

32545 32573 30421 36861

P2

P3

P4

aptraptraptr

10.25.7

16.58.3

10.66.0

11.05.8

M1

M2

M3

aptraptraptr

20.912.5

18.912.3

16.010.420.012.226.112.0

Table 36 Kanapoi Simatherium cf. S. demissum horncore measurements

30612

Lt h/c aptr

Rt. h/c aptrlt

Width between h/cs

8665

2901160

Table 37 Kanapoi Simatherium cf. S. demissum teethmeasurements

29265L 29265R

P2

P3

P4

aptraptraptr

19.1817.4718.5222.3716.7222.3

16.88

M1

M2

M3

aptraptraptr

23.124.7327.8627.4329.9825.77

27.03

30.3629.43

96

P2

P3

P4

aptraptraptr

14.649.31

20.1911.6121.6613.24

M1

M2

M3

aptraptraptr

21.7517.1827.9717.7137.9817.09

dently strongly angled on the braincase. From thewidth of the preserved portion of the braincase atthe base of the horn cores, this was evidently amuch larger animal than Damalacra species A or Bfrom Lothagam (Harris, 2003b). The base of theright horn core measures 36 mm (anteroposterior-ly) by 33 mm (transversely); the left horn core mea-sures 24 3 33 mm.

This specimen is closer to D. neanica than to D.acalla Gentry, 1980, by virtue of the uncompressedand widely divergent horn cores, but the horn coresare smaller than male representatives of this speciesfrom Langebaanweg.

Damalacra sp. A(Figure 26; Table 40)

KANAPOI MATERIAL. 64, proximal Lt. h/c;26560, proximal Lt. h/c; 29270, Rt. h/c; 30630,distal h/c frags; 30447, proximal Lt. h/c.

This species had a long, slender horn core veryreminiscent of specimens attributed to Damalacrasp. A from Lothagam (Harris, 2003b). The horncore was mediolaterally compressed with a flat-tened lateral surface. It tapers gently upward fromthe base. It is teardrop-shaped in transverse sectionwith a carinate posterior border. The horn coresdiverge outward and slightly backward from the


Figu

re26

KN

M-K

P29

270,

Dam

alac

rasp

.A,

righ

tho

rnco

re;A

5la

tera

lvie

w;

B5

med

ialv

iew

;sca

le5

5cm


Table 38 Kanapoi Hippotragini teeth measurements

32526 483 B–D

P4

M1

aptraptr

21.123.8

11.511.21913.7

M2

M3

aptraptr

20.215.525.115.9

29274

M2

M3

aptraptr

24.9114.4130.9314.1

Table 40 Kanapoi Damalacra sp. A horn core measure-ments

26560 64A 29270 30447

Rt h/c

Lt h/c

aptrltaptrlt

23.818.3

22.317.4

23.917.6

160121.118.1

Table 39 Kanapoi Reduncini tooth measurements

29275

P2

P3

P4

aptraptraptr

M1

M2

M3

aptraptraptr

13.817.618.121.822.1

75 463 29275 29276 29279 30626

P2

P3

P4

aptraptraptr

10.46.9

8.06.9

11.79.0

14.99.2

7.74.6

14.17.8

M1

M2

M3

aptraptraptr

16.19.6

15.810.7

16.011.8

17.313.019.614.331.114.8

Table 41 Kanapoi Damalacra cf. D. acalla horn coremeasurements

30157 32557

Rt h/c

Lt h/c

aptrltaptrlt

33.125.7

34.224.7

33.926

base but recurve to upright in their distal portion.There are faint transverse annulations on the an-terior surface and strong longitudinal ridges andfurrows on the lateral and medial surfaces.

Damalacra acalla Gentry, 1980

The cranium of Damalacra acalla is of similar sizeand proportions to that of D. neanica. The horn

cores are mediolaterally compressed with localized(usually medial) swelling at their bases, sometimeswith flattened lateral surface along part of theirlength, with more definite backward curvature thanin D. neanica and less marked distal divergence,inserted close behind orbits, and with a more nearlyhorizontal boundary between the top of the pediceland the horn core proper. Other differences fromD. neanica are that the braincase roof is less steeplyinclined, more curved in profile, and with a parietalhump that is as well developed as in living Dam-aliscus; the mastoid exposure is large but less ex-panded especially medioventrally, and the auditorybullae are slightly larger and much more inflated.Female horn cores are smaller than those of themales. The teeth are of similar morphology to D.neanica (after Gentry, 1980).

Damalacra cf. D. acalla(Figure 27; Table 41)

KANAPOI MATERIAL. 30157, calvaria withRt. and Lt. h/cs; 32557, proximal Rt. h/c frag;32876, distal h/c frag.

This alcelaphin is best represented by KP 30157,a calvaria with proximal horn cores that differsfrom KP 71 by its smaller size and less stronglydivergent but more strongly compressed horn cores.The horn cores are inserted close together above theorbits on long pedicels. At their base, they are ovalin transverse section. They rise upward but divergegently outward about halfway up and become morestrongly mediolaterally compressed in their distalportion. There is slight anticlockwise torsion in theright horn core when viewed from above. The faceis strongly angled on the braincase. There is a large


Figure 27 KNM-KP 30157, Damalacra cf. D. acalla, calvaria with proximal horn cores; A 5 anterior view; B 5 leftlateral view; C 5 dorsal view; D 5 right lateral view; scales 5 5 cm


Table 42 Kanapoi Alcelaphini tooth measurements

493 110 111 83 73 31739

M1

M2

M3

aptraptraptr

19.811.9

30.717.1

26.322.1

21.515.6

26.517.4

18.912.5

dP4 aptr

22.98.2

387 462 44128

M1

M2

M3

aptraptraptr

27.319.3

24.813.527.717

18.513.3

2416.8

74 108 110 30406 31733 31033 462

P2

P3

P4

aptraptraptr

5.94.5

11.16.6

14.98.2

M1

M2

M3

aptraptraptr 11.9

26.39.9 9.5

10.727.110.8

20.69.8

25.79.8

9.7

17.49.5

10.2

Table 43 Kanapoi Aepyceros sp. indet. horn core measurements

prox ap (Rt) prox tr (Rt) lt (Rt) prox ap (Lt) prox tr (Lt) lt (Lt)

7099

29277304183062732543

42

3736

33

41

3230

28

35

29

30

23

‘‘Parmularius-like’’ bulge on the top of the brain-case, midway between the horn core bases and thenuchal crest.

The shape of the calvaria and horn cores areclose to those of Damalacra acalla from Lange-baanweg but the horn cores would group in sizewith the smallest D. acalla specimens and the cal-varia has a much more pronounced parietal boss.

Alcelaphini gen. indet.(Table 42)

KANAPOI MATERIAL. 73, A 5 Lt. M1, B 5Rt. M3; 74, Lt. M3 frag; 83, Rt. M2; 108, Rt. M3;

110, Rt. M3 frag and Rt. M/; 111, Lt. M3; 287, Lt.M3; 462, Rt. M2, Lt. M3, Rt. M3 frag, tooth andbone frags; 493, Rt. dP4; 30406, Lt. mandible frags(M2–3); 31733, Lt. mandible (P2–M3); 31739, Lt.M1; 311033, Rt. M1; 44128, Lt. M3 and toothfrags.

A few alcelaphin teeth were recovered but nonewere associated with alcelaphin horn cores.

Tribe Aepycerotini

This tribe is today represented by the single butvariable species Aepyceros melampus (Lichtenstein,1812). Aepycerotins may be a sister group of thealcelaphins (Vrba, 1984) but the two groups havedifferent habitat preferences and dental morpholo-gy. Lyrate horned impalas were the dominant bovidin the Nawata Formation of Lothagam (Aepycerospremelampus Harris, 2003b). A smaller and less ly-rate-horned species predominated in the middle Pli-ocene strata of the Shungura, Nachukui, and KoobiFora Formations but the extant species had becomedominant by the late Pliocene.

Aepyceros Sundevall, 1847

Aepyceros sp. indet.(Figures 28 and 29; Tables 43 and 44)

KANAPOI MATERIAL. 70, prox Rt. h/c; 95, Lt.M2; 99, prox Lt. h/c; 106, Rt. M3; 29259, Rt. man-dible (M1–2), Lt. M2–3, Rt. M1–2; 29277, calvariaand prox Rt. h/c; 30394, Rt. M; 30417, Lt. M2;30418, prox Lt. h/c; 30627, Lt. h/c; 30633, h/cfrags; 32543, Lt. h/c; 32544, Rt. mandible (P4–M1);32546, Lt. maxilla (P2–M2); 32561, Rt. M2; 32812,Lt. maxilla frag (M1–3); 32823, Rt. M2; 36836, Lt.M1.

KP 29277 is a rather battered calvaria with theproximal portion of the right horn core but it issufficiently well preserved to confirm the genericidentification. The horn cores are mediolaterallycompressed at their base with slight lyrate curva-ture in anterior view and a gentle sigmoid curvaturein lateral view. In this regard, the Kanapoi impalamore strongly resembles A. shungurae Gentry,1985, from the northern portion of the Lake Tur-kana Basin (Gentry, 1985; Harris, 1991b) by thelack of lyration than A. premelampus Harris, 2003,from the nearby but somewhat older site of Loth-agam (Harris, 2003b). The majority of specimens


Figure 28 KNM-KP 29277, Aepyceros sp. indet., calvaria with proximal right horn core; A 5 anterior view; B 5 rightlateral view; scales 5 5 cm


Figure 29 KNM-KP 32543, Aepyceros sp. indet. left horn core; A 5 anterior view; B 5 lateral view; scales 5 5 cm


Table 44 Kanapoi Aepyceros sp. indet. teeth measure-ments

95 106 29259L 29259R 30417

M1

M2

M3

aptraptraptr

16.6

19.211.9

16.41318.512.3

13.511.116.312.8

15.311.4

32546 32561 32812 32823

P2

P3

P4

aptraptraptr

7.87.27.18.19.19.7

M1

M2

M3

aptraptraptr

11.412.215.412.7

16.511.6

14.513.2

17.112.5

29259R 32544

P4

M1

aptraptr

12.17.4

8.86.1

128.9

M2

M3

aptraptr

15.17.9

Table 45 Kanapoi Gazella sp. indet. horn core measure-ments

29264 32513

Rt h/c

Lt h/c

aptrltaptrlt

21.519.3

20.117.1

19.517.7

show slight to moderate transverse annulation; thisis most strongly developed in KP 70—the largestspecimen whose attribution to Aepyceros is slightlyless certain than that of the other specimens.

Tribe Antilopini

The Antilopini are small- to medium-sized hypso-dont antelopes that appear well adapted to arid ar-eas. The tribe has a long geological history and in-determinate species of gazelles have been reportedfrom the middle Miocene of North (Thomas, 1979)and East Africa (Gentry, 1970).

Gazella de Blainville, 1816

Gazella sp. indet.(Table 45)

KANAPOI MATERIAL. 29264, Rt. h/c frags;32513, Lt. and Rt. h/c frags.

Two specimens appear to represent the small andslightly medio-laterally compressed proximal horncores of an indeterminate species of gazelle.

Tribe Caprini

Caprins, which include domesticated sheep andgoats, are documented as common elements of themiddle Miocene assemblage from Fort Ternan(Gentry, 1970) but thereafter only appear sporadi-cally in sub-Saharan Africa as rare elements of lateNeogene biotas.

Caprini gen. et sp. indet.(Figure 30)

KANAPOI MATERIAL. 36604, Lt. h/c.A single, large left horn core with a very pro-

nounced basal sinus may represent an indetermi-nate species of goat. The horn core is strongly me-diolaterally compressed with a flattened lateral sur-face. It evidently curved backward and outwardfrom the base with a strong lyrate curvature fromthe anterior view. In some ways, it resembles a largebut very flattened impala horn core. At its base, itmeasures 45.4 mm anteroposteriorly and 31.4 mmtransversely.

Tribe Neotragini

Neotragins include about a dozen species of smallantelopes that represent the root stock from whichthe Aegodontia (alcelaphins, antilopins, caprins)emerged (Kingdon, 1982). The tribe is today re-stricted to Africa. Neotragins representing speciesof steinbuck and dikdik have been reported fromlate Miocene assemblages at Lothagam (Harris,2003b) but their small size tends to make them in-frequent components of Pliocene assemblages, al-though they are known from Langebaanweg (Gen-try, 1980) and elsewhere.

Raphiceras H. Smith, 1827

The steenboks (or steinbucks) are moderate-sizedneotragins that are distributed discontinuouslythrough open bushland or light woodland in east-ern and southern Africa. The horn cores are shortto moderately long with little mediolateral com-pression, inserted widely apart above the back ofthe orbits, are parallel to one another and, in pro-file, have a slightly concave anterior edge. Postcorn-ual fossae are present and the supraorbital pits arewide apart (Gentry, 1980).


Figu

re30

KN

M-K

P36

604,

Cap

rini

gen.

and

sp.

inde

t.le

ftho

rnco

re;A

5an

teri

orvi

ew;B

5m

edia

lvie

w;

scal

es5

5cm


Figure 31 KNM-KP 29263, Raphiceras sp. indet. frontlet with horn cores; A 5 anterior view; B 5 right lateral view;scale 5 5 cm

Table 46 Kanapoi Raphiceras sp. indet. measurements

29263

Rt h/c aptrlt

Lt. h/c aptrlt

Width between h/cs

14.312.771.613.71466.625.2

93 30443 36833 30273

P2 aptr

P3 aptr

P4 aptr

4.32.8

7.54.8

8.54.5

M1 aptr

M2 aptr

M3 aptr

10.96.3

12.06.6

17.05.8

9.56.2

10.36.7

16.36.4

6.310.47.3

Raphiceras sp. indet.(Figure 31; Table 46)

KANAPOI MATERIAL. 93, Rt. mandible (P2,M1–3); 29263, frontlet with Lt. and Rt. h/cs; 30273,Lt. M1–2; 30443, Lt. mandible (P4–M3); 36833, Rt.mandible frag (P3–4).

A frontlet with right and left horn cores (KP29263) is a little larger than the equivalent portionof an extant steinbuck cranium but is evidently con-generic. A number of neotragine dentitions that arelarger than those of dikdiks are interpreted to rep-resent this genus.

Madoqua Ogilby, 1837

The dikdiks are small, shy antelope that occur sin-gly or in pairs in dry bush country in eastern andsouthwestern Africa. The horn cores are short, of-ten keeled, compressed anterolaterally to postero-medially, and with some flattening of the postero-medial surface. They are inserted wide apart abovethe back of the orbits, parallel to one another, andnot very upright in lateral view. Postcornual fossaare small and shallow but the supraorbital pits aresmall and wide apart (Gentry, 1987).


Table 47 Kanapoi Madoqua sp. indet. tooth measure-ments

103 30207 30416 30427 30537 32547

M2

M3

P2

aptraptraptr

9.38.6

8.27.4

P3

P4

M1

aptraptraptr

4.83.364.1

6.53.7

7.34.3

M2

M3

aptraptr

7.55.1

4.7

7.24.5

10.55.1

9.55.1

11.15.1

36832 36835 36840 30206A 30206B

M2

M3

P2

aptraptraptr

6.98.287.6

P3

P4

M1

aptraptraptr

8.13.97.64.6 4.5

7.54.27.54.6

7.34.7

7.24.8

M2

M3

aptraptr

8.95.2

8.15

8.15.1 5.2

Madoqua sp. indet.(Table 47)

KANAPOI MATERIAL. 103, Rt. M3; 30206, Rt.mandible (M1–2), Rt. mandible (M1–2), Lt. M2, Rt.M3, humerus frags; 30207, Lt. mandible frag (P3–4),prox scapula, dist Lt. and Rt. humerus; 30416, Rt.mandible frags (P4, M2–3); 30427, Rt. maxilla frag(M2–3); 30537, Lt. mandible (M1–3); 32547, Rt.mandible (M2–3), seven foot bones and distal radius;36832, Lt. mandible (P4–M3); 36835, Rt. mandible(M1–2); 36840, Rt. mandible (P3–M2).

Small partial dentitions of comparable size to ex-tant dikdiks represent one of the earliest knownspecies of this genus.

PALEOENVIRONMENTS

Chronologically and stratigraphically, the KanapoiFormation is equivalent to the lower part of theNachukui Formation sequence as exposed at Loth-

agam. The lacustrine interval documented in themiddle of the Kanapoi sequence represents a south-erly extension of the Lonyumun Lake, which at thenearby locality of Lothagam is represented by theMuruongori Member. The terrestrial sediments atKanapoi may thus be correlated to an upper por-tion of the Apak Member and the lower portion ofthe Kaiyumung Member in the Lothagam succes-sion (Feibel, 2003a). More than fifty mammalianspecies have been recovered from the Kanapoi For-mation (Table 48). The percentage distribution ofthe larger herbivore families in the Kanapoi biotais broadly comparable with that seen in the ApakMember although the represented taxa suggest aslightly younger age for the Kanapoi assemblageand at Kanapoi large suids seem to have replacedpart of the bovid population that dominated atApak (Table 49).

The Nawata Formation sequence at Lothagamdocuments the interval of time in which C4 plants(and particularly grasses) underwent a major ex-pansion in Africa, Asia, and North and SouthAmerica (Cerling et al., 1997). As documented byCerling et al. (2003a:fig. 12.5), the d13C composi-tion of tooth enamel of mammals with a pure C4

diet ranges from 1–3 permil whereas that of mam-mals with a pure C3 diet in open habitats rangesfrom 212 to 216 permil. Preliminary results of iso-topic analysis of mammalian herbivores from Kan-apoi are mostly consistent with the younger radio-metric age determinations for the Kanapoi Forma-tion (Table 50). As expected, the elephantoid pro-boscideans (Anancus kenyensis, Loxodontaadaurora, Elephas ekorensis) all had a C4 grazingdiet, as did the suids Nyanzachoerus pattersoni andNotochoerus jaegeri and the equid Eurygnathohip-pus sp. All these species had assumed a grazing dietbefore or during the accumulation of the ApakMember at Lothagam. In contrast, C3 browse wasa major component of the diet of deinotheres(Deinotherium bozasi), sivatheres (Sivatherium cf.S. hendeyi), impalas (Aepyceros sp.), and ostriches(Struthio sp.). The sole rhino tooth analyzed alsoindicated a browsing diet. The d13C content of thefossil ostrich eggshell is more negative than thoseof extant ostriches from Kanapoi and the d18O ismore positive; it would appear that there was agreater proportion of C3 vegetation in the Plioceneostrich diet compared with that of modern ostrich-es on the west side of Lake Turkana. Hence, theLake Turkana Basin in the vicinity of Kanapoi ev-idently supported a variety of vegetation types andhabitats during the early Pliocene. The very positived18O values for the analyzed rhino and sivathereteeth (Table 50) suggests these animals were ob-taining most of their water from the plants thatthey ate.

Wynn (2000) recognized seven types of paleosolsat Kanapoi, all of which provide information aboutthe local ecosystem during the process of soil for-mation.


Table 48 Kanapoi mammalian faunal list

Taxon Sample size Body weight Locomotion Diet

Chiroptera

Hipposideros spp. A Ae I

Insectivora

Myosorex sp. A SA I

Macroscelidae

Elephantulus sp. A SA I

Lagomorpha

Leporidae gen. and sp. indet. C T Hg

Rodentia

Tatera sp.Murini gen. indet.Xerus sp.cf. Steatomys sp.

AABA

SASATT

HbHbHFHb

Carnivora

Enhydriodon ekecamancf. Torolutra sp.Parahyaena howelliDinofelis petteri

11

313

DCED

AqAqTT-S

CCCC

Homotherium sp.Felis sp.Helogale sp.Genetta sp. nov.

4123

ECBC

T-ST-STT

CCCC

Primates

Australopithecus anamensiscf. Galago sp. indet.cf. Ceropithecoides sp. indet.Colobinae sp. AColobinae sp. BParapapio adocf. Theropithecus sp.

591681

501

D/EBCDDDD

TAATATATATATA

OOHFHFHFHFHF

Proboscidea

Deinotherium bozasiAnancus kenyensisElephas ekorensisLoxodonta adauroraLoxodonta exoptata

52

25261

HHHHH

TTTTT

HbHgHgHgHg

Perissodactyla

Ceratotherium praecoxDiceros bicornisEurygnathohippus sp. indet.

114

34

HHF

TTT

HgHbHg

Artiodactyla

Hexaprotodon protamphibiusHexaprotodon sp.Nyanzachoerus pattersoniNotochoerus jaegeriNotochoerus cf. N. euilus

601

77291

HHFFF

AqAqTTT

BGBGHgHgHg

Giraffa stilleiGiraffa jumaeGiraffa sp. indet.Sivatherium cf. S. hendeyiTragelaphus kyaloae

5193

33

GHGGF

TTTTT

HbHbHbHbBG


Table 48 Continued

Taxon Sample size Body weight Locomotion Diet

Tragelaphini gen. indet.Simatherium cf. S. demissumHippotragini gen. indet.Kobus sp.Reduncini gen. indet.

174426

FHGFF

TTTTT

BGHgBGHgHg

Damalacra cf. D. neanicaDamalacra sp. ADamalacra cf. D. acallaAlcelaphini gen. indet.Aepyceros sp.

153

1418

FEFFF

TTTTT

HgHgHgHgHb

Gazella sp.Caprini gen. and sp. indet.Raphiceras sp.Madoqua sp.

215

10

DEDC

TTTT

HgHgHbHb

Ecovariable categories

Code Body weight Code Locomotor patterns Code Feeding preferences

ABCDE

0–100 g100–1,000 g

1–10 kg10–45 kg45–90 kg

TTASAAS

TerrestrialTerrestrial–arborealSemiarborealArborealScansorial

IFHFHbHg

InsectivoreFrugivoreHerbivore–frugivoreBrowserGrazer

FGH

90–180 kg180–360 kg3601 kg

TSAqAeFTF

Terrestrial–scansorialAquaticAerialFossorialTerrestrial–fossorial

BGCCIO

Browser–grazerCarnivoreCarnivore–insectivoreOmnivore

1. Modern analogues of the Aberegaiya paleosolsare found throughout semiarid regions of EastAfrica on floodplains flanking large river sys-tems and support edaphic savanna grasslandswithin low tree–shrub savanna mosaics.

2. The Lorenyan paleosol is found in delta depositswhere it represents brief emergence of the deltaflats and desiccation of the clayey parent mate-rial; modern analogues occur on the Omo RiverDelta at the north end of Lake Turkana wherethey support sparsely vegetated grasslands withvariable admixtures of ephemeral forbs.

3. Dite paleosols, from which most of the hominidfossils were derived, were better drained butformed in broadly similar conditions to theAberegaiya and Lorenyang paleosols. Modernanalogues to the Dite paleosols are found in thelower Omo Valley, where well-drained soils sup-port low tree–shrub savanna vegetation in semi-arid to arid climatic regimes.

4. Abilat paleosols are calcic xerosols. Their char-acteristics are intermediate between Dite andAberegaiya paleosols and they are believed torepresent transitional habitats between thesetwo pedotypes. Vegetation growing on Abilatsoils would thus have been transitional betweenthe forb-dominated edaphic grasslands of the

Aberegaiya pedotype and the low tree–shrub sa-vanna of the Dite pedotype.

5. The Nasua paleosol is found on delta sediments.Like the Lorenyang, the Nasua paleosol repre-sents brief emergence of the delta flats but sup-ported denser vegetation; similar modern clayeysoils are found on the Omo Delta, where theysupport shrub thickets of aquatically adaptedAcacia and Cadaba species.

6. Kabisa paleosols with vertical rhizoliths arefound in channel sandstones in the upper fluvialseries; modern counterparts in the lower Tur-kana Basin occur in the sandy soils of ephemeralchannels, where they support gallery woodlandand thicket vegetation—often dominated byAcacia tortilis.

7. Akai–Ititi paleosols have horizontal rhizolithsrepresenting root mats in nearshore environ-ments where groundwater is shallow; modernanalogues fringe the Omo Delta and supportlakeside and streamside grasslands with rootmats of Phragmites, Typha, and Cyperus speciesand Loudetia phragmatoides or Sporobolis spi-catus.

Wynn’s (2000) overall interpretation of the pre-vailing habitats at Kanapoi was that they stronglyresembled habitats that presently occur in the re-


Table 49 Percentage distribution of large herbivores at Lothagam and Kanapoi

Lr Nawata Ur Nawata Apak Kanapoi Kaiyumung

ElephantoideaRhinocerotidaeEquidaeHippopotamidae

4.734.73

10.1120.65

1.975.90

11.5218.54

11.265.308.61

12.58

13.954.268.04

14.42

1.526.06

13.640.00

SuidaeGiraffidaeBovidae

24.522.80

32.47100.00

18.822.53

40.73100.00

13.255.96

43.05100.00

25.064.26

30.02100.01

36.364.55

37.88100.00

Table 50 Results of stable isotope analysis of Kanapoiherbivores

d13C d18O

Struthio sp.

WT 3597 28.66 10.89

Anancus kenyensis

KP 30442 20.13 21.11

Elephas ekorensis

KP 30173WT 3570

21.7421.48

21.322.37

Loxodonta adaurora

KP 390301963019630596KP 383

22.7322.522.3421.0822.99

0.871.051.092.2

20.36

Deinotherium bozasi

WT 3617 212.43 21.75

Rhinocerotidae gen. indet

WT 3223 29.98 4.71

Eurygnathohippus sp.

30233 1.24 2.09

Nyanzachoerus pattersoni

KP 205WT 3222 (M3)KP-X10

26.521.9421.19

1.191.14

20.22

Notochoerus jaegeri

KNM-3348 BKP 241KP 265WT 3227

21.7422.0125.4721.74

1.431.07

22.191.78

Sivatherium cf. S. hendeyi

KP 30227 29 8.6

Aepyceros sp.

WT 3240-AepyWT 3240

210.0229.77

1.361.46

gion of the modern Omo River Delta at the northend of Lake Turkana. Most of the hominids derivefrom Dite paleosols that he interpreted to have sup-ported low tree–shrub savanna vegetation in asemiarid climate with an annual rainfall thatranged from 350 to 600 mm. Wynn (2000) sug-gested that Kanapoi may represent the earliestknown occurrence of hominids venturing into rel-atively open habitats. However, Ward et al. (1999)caution that many of the hominid specimens showevidence of carnivore damage. Thus, it is possiblethat the hominid remains were transported by car-nivores to the locations where they accumulated.Other paleosols ranged from poorly drained Verti-sols with forb-dominated edaphic grassland in localshallow depressions to well-drained alluvial soilssupporting gallery woodland adjacent to streamcourses. The proportion of soil carbonate contrib-uted by C4 plants (i.e., grasses) ranges from 25%in the Kabisa paleosol to 40% in the Dite and Abi-lat paleosols (Wynn 2000).

Confirmation of the nature of the terrestrialhabitats during the interval that the early Plioceneassemblage accumulated at Kanapoi is providedby the dietary adaptations of the terrestrial ver-tebrate fossils (Table 48). Proboscideans amountto about 14% of the large vertebrate biota: Lox-odonta adaurora and Elephas ekorensis predomi-nate, whereas Anancus and Deinotherium are onlysparsely represented. Elephantids and gomphoth-eres had acquired a grazing diet by the beginningof the Pliocene and their presence at Kanapoi ap-pears to signify open habitat in the near vicinityof the Kanapoi Delta, although the presence ofDeinotherium confirms an ample supply of C3

vegetation. Rhinos were represented by the pre-decessors of the two extant African species, bothof which had acquired their different (grazing ver-sus browsing) dietary specializations by the begin-ning of the Pliocene. Equids are represented byEurygnathohippus, a grazing hipparionine. Largesuids are represented by Nyanzachoerus patter-soni and Notochoerus jaegeri; both were inter-preted as closed habitat species by Bishop (1994)on the basis of their postcranial anatomy but bothspecies were evidently specialized grazers on thebasis of the isotopic composition of their tooth


Table 51 Stratigraphic distribution of bovid tribes at Lothagam and Kanapoi

Lr Nawata Ur Nawata Apak Kanapoi Kaiyumung

TragelaphiniBoviniBoselaphiniHippotraginiReduncini

3.331.33

24.675.33

11.33

2.082.087.645.56

21.53

20.639.523.174.769.52

39.373.15

3.947.09

16.0028.00

8.00AlcelaphiniAepycerotiniAntilopiniNeotragini

4.6748.000.670.67

100.00

17.3640.281.392.08

100.00

14.2931.754.761.59

100.00

18.1114.172.36

11.81100.00

12.0036.00

100.00

Figure 32 Graph depicting ecological structural analysis of frugivorous mammals and nonarboreal mammals from mod-ern African habitats and from Pliocene assemblages from the Lake Turkana Basin. Data for extant habitats and assem-blages from the Shungura and Koobi Fora Formations are from Reed (1997); those for Lothagam assemblages are fromLeakey and Harris (2003); those for Aramis are from WoldeGabriel at al. (1994). Of the two data points representingKanapoi, that on the right is for the assemblage from below the lacustrine interval, that on the left is for the assemblagefrom above the lacustrine interval

enamel (Harris and Cerling, 2002; Cerling et al.,2003b). Giraffids were relatively uncommon con-stituents of the Kanapoi assemblage but both siv-atheres and giraffines were C3 browsers at thatpoint in time. Bovids, as usual, are the most com-monly encountered terrestrial herbivores. Trage-laphins, aepycerotins, and neotragins—now allclosed habitat or forest-edge forms—make up twothirds of the Kanapoi bovid assemblage, but thepresence of bovins, reduncins, hippotragins, and

alcelaphins is indicative of nearby sources ofgrass. In contrast with the bovid assemblages fromthe Apak and Kaiyumung Members, the Kanapoibovid assemblage has more tragelaphins and al-celaphins but fewer bovins and aepycerotins—which may be interpreted to represent drier andless wooded habitats in the vicinity of Kanapoi(Table 51). Overall, grazing species outnumberbrowsing species by a ratio of nearly two to one;in terms of numbers of individuals, browsers out-


Figure 33 Graph depicting ecological structural analysis of fresh grass grazing mammals and terrestrial mammals frommodern African habitats and from Pliocene assemblages from the Lake Turkana Basin. Data points as for Figure 32

number grazers by three to one. In confirmation,the Kanapoi small mammals suggest a relativelydry climate and open habitat (Appendix).

The Kanapoi large-mammal assemblage sharesmany elements with that from the 4.4 Ma site ofAramis, Ethiopia (WoldeGabriel et al., 1994), al-though, with the exception of the primates, mostof the Aramis fossil material has yet to be describedin detail. Taxa shared by Kanapoi and Aramis in-clude elephantids (unidentified at Aramis), Anan-cus, Deinotherium, Ceratotherium cf. C. praecox,‘‘Hipparion’’ sp., Hexaprotodon sp., Nyanzachoe-rus pattersoni, Notochoerus jaegeri, a large andsmall species of Giraffa, and tragelaphins, bovins,and neotragins. However, with the exception of anunidentified kudu (Tragelaphus sp.), large verte-brates are rare at Aramis, as are aquatic verte-brates. WoldeGabriel et al. (1994) interpret thedominance of colobines and kudus at Aramis to bea strong indication of a closed, wooded environ-ment. However, the presence at an early Pliocenesite of elephantids, Anancus, Ceratotherium, anequid, a hippo, Nyanzachoerus, Notochoerus, andbovins is indicative of a diverse open-country graz-ing component in the biota. Moreover, the largergenera of early Pliocene colobines were more ter-restrial than their extant counterparts (Leakey etal., 2003) and hence the dominance of colobinesmay not necessarily mandate the presence of closedwoodland. As at Aramis, tragelaphins were the

most abundant bovids recovered from Kanapoi.However, in contrast with the situation at Aramis,papionin primates far outnumbered the colobines.On balance, Kanapoi would appear to representhabitats that were similar to but more open thanthose of Aramis. Andrews and Humphrey (1999)stated that the fossil assemblages from both Aramisand Kanapoi are underrepresented by small mam-mals that often provide a more precise assessmentof the prevailing paleoenvironments than do largemigratory species. Large quantities of micromam-mals that were retrieved by the National Museumsof Kenya expeditions have yet to be studied in de-tail (see Appendix) and the bulk of the nonprimatecomponent of the Aramis fauna has also yet to bestudied in depth.

Ecological diversity provides a different meansfrom taxonomic uniformitarianism for analyzingthe community structure of fossil mammalian fau-nas in order to obtain information about the hab-itats represented by faunal assemblages (Andrewset al., 1979). Using this methodology, Andrews andHumphrey (1999) interpret the Kanapoi materialcollected by American expeditions in the 1960s, as‘‘. . . dominated by medium- to large-sized terres-trial species and both browsers and grazers are wellrepresented. The high terrestrial component in thefauna places it with the drier end of the present-day woodland and bushland ecosystems suggestingopen woodland with abundant grass.’’


Ecological structural analysis as formulated byReed (1997) provides a different interpretation.Reed established that habitats were predicted by lo-comotory adaptations and characterized by trophicecovariables and found that it was possible to dif-ferentiate between different terrestrial habitats byplotting the percentage of frugivorous mammalsagainst the percentage of nonarboreal mammals(Reed, 1997:fig. 5A). Similar results were obtainedby plotting the percentage of fresh grass grazersagainst percentage of terrestrial mammals and thisalso established the presence/absence of edaphicgrassland (Reed, 1997:fig. 5B). The estimated bodyweights, locomotor adaptations, and feeding pref-erences for the Kanapoi mammals are listed in Ta-ble 48. When Pliocene assemblages from the LakeTurkana Basin are superimposed on the modernhabitat plots for frugivores versus nonarborealmammals (Fig. 32), the two Kanapoi assemblages(above and below the Lonyumun Lake incursion)plot with the closed woodland assemblages. A sim-ilar grouping occurs when the Kanapoi assemblagesare superimposed on the graph of fresh grass graz-ers versus terrestrial mammals (Fig. 33). In bothcases, the Kanapoi assemblages plot close to thosefrom the Kaiyumung Member at Lothagam andShungura Member B in the lower Omo Valley. Thereason why the Kanapoi assemblages appear to in-dicate closed woodland is because the primateshave been interpreted as at least partly arboreal (re-quiring shelter in trees at night). Attribution of ter-restrial adaptation to one or more of the primatespecies would skew the sample toward an interpre-tation of more open habitat. Given that the homi-nin was bipedal and that early Pliocene cercopith-ecoids were more terrestrial than later forms, suchan interpretation would be more in keeping withthe dietary adaptations of the fossil species and theecological adaptations of their modern counter-parts.

SUMMARY

The early Pliocene site of Kanapoi, southwest ofLake Turkana in northern Kenya, has yielded theoldest australopithecines from eastern Africa al-though a similar age has recently been claimed fora new australopithecine locality in southern Africa(Partridge et al., 2003). Associated with the homi-nin remains from Kanapoi is a diverse vertebratefauna that has been recovered from fluvial and la-custrine sediments dating between 4.17 and 4.07Ma. The Kanapoi tetrapod fauna is much moreprolific than that from any other similarly aged lo-cality elsewhere in the Lake Turkana Basin (Nachu-kui and Koobi Fora Formations). The assemblageincludes 24 species of fish, 7 species of chelonians,4 species each of crocodylians and birds, and over50 species of mammals. Few of the recognized spe-cies are new but micromammals have not yet beenthoroughly investigated. Relatively complete suidspecimens mandate the transfer of the species

Nyanzachoerus jaegeri to the genus Notochoerus.Paleosols associated with the fauna remains suggesta mixture of open and closed habitats similar tothose currently found in the vicinity of the OmoDelta at the north end of Lake Turkana. Such aninterpretation is supported by the dietary adapta-tions of the herbivorous fossil mammals and thehabitats exploited by their living representatives.

ACKNOWLEDGMENTS

We thank the Government of Kenya and the Trustees ofthe National Museums of Kenya for permission to studythe Kanapoi fossils and the directors of the National Mu-seums of Kenya and Natural History Museum of Los An-geles County for logistical support that helped expeditethis manuscript. Fieldwork at Kanapoi was funded by theNational Geographic Society and National Science Foun-dation (SBR 9601025) and made possible by donations offuel by Caltex (Kenya) and the loan of light aircraft be-longing to Jonathan and Richard Leakey. We thank alsothe preparation and curatorial staff of the Division of Pa-laeontology at the National Museums of Kenya, Nairobi,and the many people who participated in the 1994–97field expeditions and whose names are acknowledged inWard et al. (2001). We gratefully acknowledge helpful dis-cussions with Craig Feibel, Nina Jablonski, Kathy Stew-art, Lars Werdelin, and Alisa Winkler, and we thank HankWesselman for his observations on the Kanapoi micro-mammals, Diana Mattheissen for her notes on the Kana-poi birds, and Anthony Macharia for his help with theGIS database. Isotopic analyses were undertaken in theGeochemistry and SIRFER Laboratories of the Universityof Utah and were underwritten by support from NSF andthe Packard Foundation. Drs. Nina Jablonski and TimWhite, an anonymous referee, and members of the Sci-entific Publications Committee for the Natural HistoryMuseum of Los Angeles County, who kindly offered sug-gestions that helped improve the manuscript.

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APPENDIX

PRELIMINARY ASSESSMENT OF THE KANAPOI MICROMAMMALS

ALISA J. WINKLER

Order Chiroptera

Family Hipposideridae

Hipposideros Gray, 1831

Hipposideros spp.

Winkler (1998) reported a large and small species of Hip-posideros (Old World leaf-nosed bats), represented mainly

by postcrania and isolated teeth, from the ‘‘Bat Site’’ lo-cality (WT 3409). In Africa, Hipposideros is currentlyknown from seven superspecies or species groups (King-don, 1974). Hipposideros may roost in a variety of shel-ters, including caves, holes in the ground, hollow trees,and in undergrowth. Several species are known to roostwith other species of bats. The size of roosting aggrega-tions varies from several to over 1,000 individuals. At the‘‘Bat Site’’ locality, the large concentration of bats, relative


scarcity of other taxa, and little evidence of alteration ortransport of the bones and teeth suggest that this assem-blage represents an attritional accumulation under a roostsite.

Order Insectivora

Family Soricidae

Subfamily Crocidurinae

Crocidurinae gen. and sp. indet.

Two incomplete mandibles of shrews are currently knownfrom Kanapoi. At least one of these may be referable toMyosorex Gray, 1838. This genus is known from Africaat present and is also reported from the African Plio–Pleis-tocene (Hendey, 1981; Wesselman, 1984).

Order Macroscelidea

Family Macroscelididae

Elephantulus Thomas and Schwann, 1906

Elephantulus sp.

Three specimens of Elephantulus have been recovered sofar from Nzube’s Mandible Site (WT 3227). Kanapoi in-cludes one of the earliest known records of the genus, theother being Langebaanweg (Hendey, 1981). The presentrange of E. rufescens (Peters, 1878) (spectacled or long-eared elephant shrew) includes thickets in South Turkana(Coe, 1972).

Order Lagomorpha

Family Leporidae

Leporidae gen. and sp. indet.Dental and postcranial remains of lagomorphs are knownfrom Nzube’s Mandible Site and several other sublocalitiesat Kanapoi. Lagomorphs are well represented in modernand fossil African faunas.

Order RodentiaWinkler (1998) reported a rich microvertebrate fauna as-sociated primarily with the locality that yielded the holo-type mandible of Australopithecus anamensis (Nzube’sMandible Site). Recovered materials included cranial andpostcranial remains of fish, amphibians, reptiles, birds,and mammals. The microvertebrates from Nzube’s Man-dible Site likely represented a concentration of owl pellets,with some attritionally incorporated taxa. The mamma-lian specimens were dominated by a small species of thegerbil Tatera Lataste, 1882, and by murine rodents. Thereis also a new species of ground squirrel (Xerus) Hemprichand Ehrenberg, 1832, and a new dendromurine genus thatappears to be the sister taxon to Steatomys Peters, 1846,(fat mice). Although the Kanapoi rodents have yet to bestudied in detail, the fauna appears most similar to thatfrom the lower Shungura Formation of the lower OmoValley (Wesselman, 1984). At the generic level, the Kan-apoi rodents are strikingly similar to those present todayin the South Turkana region (Coe, 1972). Based on a com-parison with modern analogues, the Kanapoi small mam-mals suggested a relatively dry climate and open habitat.



CARNIVORA FROM THE KANAPOI HOMINID SITE, TURKANA

BASIN, NORTHERN KENYA

LARS WERDELIN1

ABSTRACT. Kanapoi is the earliest Pliocene site yet described in eastern Africa with a substantial carni-voran record. It includes eight species in as many genera, representing five families. The material is dom-inated by the hyaenid Parahyaena howelli n. sp., but also includes a new Enhydriodon species, E. ekeca-man, the lutrine cf. Torolutra sp., the felids Dinofelis petteri, Homotherium sp., and Felis sp., the herpestidHelogale sp., and the viverrid Genetta n. sp. The Kanapoi Carnivora includes the remains of the first post-Miocene radiation of endemic African Carnivora.

INTRODUCTION

The earliest Pliocene (here taken as ca. 5.2–4.0 Ma)has provided relatively few eastern African locali-ties containing mammalian fossils compared withthe million years that followed. Most of the local-ities that do exist from this time interval have eitherfew carnivores associated with them or are as yetundescribed. Thus, the Apak Member at Lothagamincludes only four carnivore taxa (Werdelin, 2003),the Lonyumun Member of the Koobi Fora Forma-tion three (Werdelin and Lewis, unpublished), theKataboi Member of the Nachukui Formation andKosia (also West Turkana) also three (personal ob-servations). Outside of Kenya, localities of this timeperiod from Uganda have also yielded few carni-vores (Petter et al., 1991). A richer site is Aramis,in Ethiopia, although the carnivores there have yetto be described (Howell, personal communication).Kanapoi, with its somewhat larger sample of car-nivores, thus adds significantly to our knowledge ofcarnivoran evolution in the earliest Pliocene of east-ern Africa.

The bulk of the material discussed herein wasobtained by the National Museums of Kenya ex-peditions to Kanapoi in the early 1990s. However,a few carnivore specimens were recovered by theearlier American expeditions. These have beenmentioned a few times in the literature under var-ious guises (Behrensmeyer, 1976; Savage, 1978;Howell and Petter, 1980; Turner et al., 1999). Inparticular, Behrensmeyer (1976) lists Enhydriodonn. sp., Hyaena sp., and Machairodontinae indet. aspresent at Kanapoi. Of these, the first is here stillreferred to Enhydriodon Falconer, 1863, the secondto Parahyaena Hendey, 1974, while the third ishere listed as Carnivora indet., as it cannot be de-termined if the specimen belongs to DinofelisZdansky, 1924, or Homotherium Fabrini, 1890.The remaining taxa described below are new to theKanapoi fauna.

1. Department of Palaeozoology, Swedish Museum ofNatural History, Box 50007, S-104 05, Stockholm, Swe-den.

CONVENTIONS AND ABBREVIATIONS

Kanapoi fossils in the collections of the NationalMuseums of Kenya are formally accorded the ac-ronym KNM-KP before the accession number; tosave repetition, this acronym is omitted from thelists of Kanapoi specimens and abbreviated to KPin the body of the text.

Tooth abbreviations in upper case (I, C, P, M)indicate upper teeth; those in lower case (i, c, p, m)indicate lower teeth. Hence M1 is the upper firstmolar, p4 is the lower fourth premolar. The follow-ing abbreviations are used in the text and tables:

a-p 5 anteroposteriorDist 5 distal

L 5 anatomical length (long bones); mesio-distal length (teeth)

LpP4 5 length of main cusp of P4

MC 5 metacarpalMT 5 metatarsalmax 5 maximummin 5 minimum

Prox 5 proximalSust 5 sustentaculum

transv 5 transverseW 5 buccolingual width

WaP4 5 anterior width (including protocone) ofP4

WblP4 5 minimum blade width of P4


Order Carnivora

Family MustelidaeGenerally speaking, mustelids are rare in the fossilrecord of eastern Africa. For the most part, thismay reflect a preservational bias against smallerspecies of Carnivora. However, those localities thatare particularly rich in smaller Carnivora also differamong themselves in the richness and diversity oftheir mustelids. Thus, Hadar is rich in small mus-telids (personal observations), while Olduvai hasfewer taxa, despite the smaller Carnivora beingwell represented at the latter site (Petter, 1973).


Figure 1 Enhydriodon n. sp., A, KP 10034A, right P4 inocclusal view; B, KP 10034B, right m1 in (top) occlusaland (bottom) lingual view; C, KP 10034C, right M1 inocclusal view. In A and C, anterior is to the right; in B,anterior is to the left

This variation may reflect real differences in paleo-ecology between the sites. Nevertheless, the major-ity of mustelids found in the eastern African fossilrecord are larger species of the genera MellivoraStorr, 1780, Enhydriodon and Torolutra Petter,Pickford, and Howell, 1991. Kanapoi is no excep-tion to this pattern, with both of the latter generarepresented.

Enhydriodon Falconer, 1863

The genus Enhydriodon encompasses a number ofspecies of Enhydrini (sea otters) of large to verylarge size. The genus is known from the Siwaliksof Pakistan and India, where it was first described(Lydekker, 1884; Willemsen, 1992). However, themain diversity within Enhydriodon is found in Af-rica, with several species of varying size knownfrom a number of localities dating between ca. 6.0Ma (Lukeino Formation; Pickford, 1978) and ca.2.5 Ma (Omo, Shungura Formation MembersE1F; Howell and Petter, 1976). The Kanapoi ma-terial represents one of the earlier members of thislineage.

Enhydriodon ekecaman sp. nov.(Figure 1)

Enhydriodon n. sp. Behrensmeyer, 1976Enhydriodon pattersoni Savage, 1978 (nomen nu-

dum)Enhydriodon pattersoni Turner, Bishop, Denys, and

McKee, 1999 (nomen nudum)

DIAGNOSIS. Differs from Siwalik Enhydriodonin its smaller size. Differs from E. africanus Strom-er, 1931 (the other described African Enhydriodon)by having a broader m1 with a more open talonid

basin and relatively smaller paraconid, more robustand larger M1 hypocone(s) and more stoutly builtP4.

HOLOTYPE. KNM-KP 10034, A 5 right P4(Fig. 1A), B 5 right m1 (Fig. 1B), C 5 right M1(Fig. 1C), D 5 right C). Written documentation re-garding the association in the field of these fourspecimens was provided by Dr. J. C. Barry (in cor-respondence). Given this information, it is reason-able to assume that all four belonged to a singleindividual and therefore the entire hypodigm ischosen as the holotype of this new species.

ETYMOLOGY. After the Turkana ‘‘ekecaman,’’meaning fisherman. The diet of this animal wascomposed at least in part of fish.

KANAPOI MATERIAL. 10034; associated teeth(holotype).

MEASUREMENTS. KP 10034A, buccal length5 16.5; KP 10034B, total length 5 21.2, trigonidlength 5 11.5, talonid length 5 9.3, trigonid width5 13.3, talonid width 5 13.5; KP 10034C, buccallength 5 12.1, lingual length 5 15.8, anteriorwidth 5 19.8, posterior width 5 19.0. Measure-ments defined as in Willemsen (1992).

The right upper carnassial, KP 10034A (Fig. 1A),is missing the protocone and most of the hypoconeand posterior shelf. The parastyle is short and lowbut has a distinct anterior cusp. The paracone ishigh and much the largest buccal cusp. There areblunt crests leading anteriorly to the parastyle, an-terolingually toward the protocone and posteriorlytoward the metacone. The latter crest is interruptedby a shallow valley before it meets the metacone.The latter cusp is set far posteriorly and is muchlower and smaller than the paracone. There was anextensive basin formed posterobuccally to the hy-pocone and the posterobuccal corner and posteriormargin of the tooth lie at nearly right angles to theanteroposterior axis of the tooth. The cingulum ex-tends along the entire preserved part of the toothexcept for the posterobuccal corner.

The right lower carnassial, KP 10034B (Fig. 1B)is low, broad, and stoutly built. The three trigonidcusps are all low and pyramidal with their majoraxes directed either anteroposteriorly (protoconid,metaconid) or transversely (paraconid). In occlusalview, the paraconid is the smallest of the threecusps but all three are worn down to about thesame height. The apex of the paraconid is set slight-ly lingual to the middle of the cusp and it is alsoslightly broader lingually than buccally. The apexof the protoconid is set slightly anterior to the mid-dle of the cusp. There is a blunt crest that runsdown the lingual side of this cusp toward the tal-onid, making the cusp almost diamond-shaped,though with a gently curved buccal side. Anteriorly,the protoconid is separated from the paraconid bya shallow valley. Posteriorly, the accessory proto-conid cusp is very weakly developed, merely form-ing a low bulge on the posterior face of the cusp.The metaconid is set slightly posterior to the pro-toconid. Its apex is at the middle of the cusp. The

Werdelin: Carnivorans m 117

cusp is triangular in occlusal view, with the apex ofthe triangle directed toward the buccal side. Ante-riorly, the metaconid is separated from the para-conid by a deep valley. Between the trigonid cuspsis formed a shallow, flat basin that is about 3 mmwide and 2 mm long. The talonid basin is low andwide. The entoconid is well developed but low. Inocclusal view, it is about the size of the paraconid.None of the other talonid cusps is well defined. In-stead, they form a low, broad, gently undulatingridge surrounding the central basin. The buccal cin-gulum is strong and extends from the anteriormostpart of the tooth to the posterior end of the hypo-conid.

The right M1, KP 10034C (Fig. 1C), is broad,low, and robust, with a very broad lingual basin.The paracone is small, and buccal to it, there is alarge parastyle, which is in fact larger than theparacone itself. The paracone is low and worn andconnected to the metacone by a narrow valley. Themetacone is considerably higher and larger than theparacone and has a pyramidal base. It is set at theposterior margin of the tooth. Lingual to the meta-cone and separated from it by a narrow valley thereis a metaconule that is almost as large as the meta-cone itself. This cusp is also set at the posteriormargin of the tooth. Lingual to the metaconulethere is a wear facet for occlusion with m2. Thiswear facet is confined to the posterior margin ofthe tooth. At the posterolingual corner of the tooththere is a large swelling of the cingulum, forming alow cusp. The protocone is double, with one cuspset slightly anterobuccal to the other. These twocusps are of about equal size. The cingulum runsaround the entire tooth, except anteromedially,where it is worn down by the wear facet for P4,and posterolingually, where the aforementioned m2wear facet is located. The cingulum is otherwiseweakest around the metacone.

The right C, KP 10034D, is short and straight,with a crown that is only slightly longer than it iswide. The tip is worn flat. There is a strong medialcingulum but no lateral one.

DISCUSSION. The material of Enhydriodonfrom Kanapoi is limited, but can nevertheless bedistinguished from other African Enhydriodon ofsimilar age. The lower carnassial, for example, dif-fers from that of E. africanus from Langebaanwegamong other features in being shorter and relativelywider, in the somewhat more widely spaced trigo-nid cusps, and in the flatter and more open talonidbasin (cf. Hendey, 1978b). The development of theposterolingual cusplets is more pronounced in theKanapoi form. The M1 differs from a partial M1from Kosia (West Turkana, ca. 4.0 Ma) in that theanterolingual corner of the Kanapoi M1 forms anearly right angle, while the homologous angle ofthe Kosia tooth is closer to 135 degrees (personalobservations). The Kanapoi Enhydriodon furtherdiffers from younger Enhydriodon from formationssuch as Hadar, Koobi Fora, and Shungura in itsmuch smaller size. Hence, we can infer that the

Kanapoi Enhydriodon belongs to a hitherto un-known species of that genus, a species that is notat present known from any other site. All four En-hydriodon teeth from Kanapoi originate from theAmerican expeditions (1966–72) and were collect-ed in 1967.

Torolutra Petter, Pickford, and Howell, 1991

Torolutra is a genus of otters similar in size to theliving European otter Lutra lutra (Linnaeus, 1758),or slightly larger. Only a single species, T. ougan-densis, has been described (Petter et al., 1991). Thismaterial is from Nyaburogo and Nkondo in Ugan-da, while the species has also been tentatively iden-tified from Ethiopia in the Usno Formation of theOmo Group. These localities bracket Kanapoi inage.

cf. Torolutra sp.

KANAPOI MATERIAL. 30155, right I3, left andright P4 fragments, premolar fragment, m1 talonidfragment, proximal left radius fragment, proximalright tibia fragment, humerus shaft fragment, par-tial cervical, thoracic and caudal vertebrae, assort-ed indeterminate fragments.

The I3 is strongly recurved and has a shortcrown. The enamel reaches farther down on thelateral than on the medial side. There is a promi-nent cingulum surrounding this tooth. This cingu-lum is best developed on the medial side. The rootof I3 is relatively straight. The P4 preserves the me-tastyle, a partial paracone and a part of the lingualprotocone shelf. There is no carnassial notch. Theprotocone shelf is not as long as in Enhydriodon,being instead more similar to that of Lutra Brisson,1762. The m1 preserves the posterior part of thetalonid, with a prominent hypoconid and lowbumps indicating entoconulid and entoconid. Thecingulum is prominent around the posterior end ofthe tooth. The proximal radius fragment is smalland broken. The proximal tibia fragment showsonly parts of the proximal articular surface. All thevertebrae are relatively robust, the proximal caudalvertebra extremely so, while the cervical vertebraeare relatively much smaller.

DISCUSSION. These specimens compare well, asfar as comparisons can be made, with specimens ofTorolutra ougandensis described by Petter et al.(1991). They are a little larger than the specimensfrom Uganda, but match the Omo specimens fig-ured by those authors quite well.

Family HyaenidaeHyenas are common elements in eastern AfricanMio–Pliocene faunas. As in Eurasia, there is an ex-tinction event at the end of the Miocene that elim-inates the dominant ‘dog-like’ hyenas that are stillpresent at localities such as Lothagam (Werdelin,2003). At Pliocene localities, hyenas are mainly rep-resented by relatives of the living hyenas. These Pli-ocene forms had adaptations to a scavenging life-


style similar to those of living hyenas, but less ac-centuated. At Laetoli, hyenas are abundant, and in-clude fossil relatives of three of the four livinghyenas (Werdelin, unpublished). One of these spe-cies is also present at Kanapoi.

Parahyaena Hendey, 1974

There has been some debate regarding the validityof Parahyaena as a genus distinct from Hyaena(Werdelin and Solounias, 1991; Jenks and Werde-lin, 1998). On the one hand, today these are twomonospecific sister taxa, and from this perspective,generic distinction may be deemed unnecessary. Onthe other hand, the split between the two, as in-ferred from both molecular and paleontological ev-idence, extends down into the Miocene, and mostgeneric splits among carnivores are of about thisage or even younger. From this perspective, genericseparation is valid. Here I follow the latter path, asI believe that geological age is the only criterionwith which to resolve ranking issues when thesebecome critical. Until now, Parahyaena was knownfrom the single extant species P. brunnea (Thun-berg, 1820), which has a limited distribution andgeological age (Jenks and Werdelin, 1998). A singlerecord extends the range of P. brunnea into easternAfrica in the middle Pleistocene (Werdelin and Bar-thelme, 1997). This makes the presence of an an-cestral species of Parahyaena at Kanapoi highly sig-nificant.

Parahyaena howelli sp. nov.(Figures 2–5)

Hyaena sp. Behrensmeyer, 1976Pachycrocuta sp. Howell and Petter, 1980

DIAGNOSIS. Hyaenid of large size (larger thanHyaena hyaena Linnaeus, 1758). Mandibular ra-mus robust, premolars moderately developed forbone cracking (weaker than in Pliocrocuta Kretzoi,1938, Pachycrocuta Kretzoi, 1938 and CrocutaKaup, 1828). Masseteric fossa clearly subdividedby a ridge into a ventral and dorsal part (unlike H.hyaena). Metastyle of P4 clearly longer than para-cone (unlike Ikelohyaena abronia (Hendey, 1974)and H. hyaena). Metacarpals short and robust (un-like all modern hyenas).

HOLOTYPE. KNM-KP 30235, associated par-tial skeleton (Figs. 2, 3).

ETYMOLOGY. After Dr. F. Clark Howell, lead-ing scholar of African fossil carnivores.

KANAPOI MATERIAL. 10033, complete rightmandibular ramus with c–m1 (Fig. 2A, Hyaena sp.in Behrensmeyer 1976; Pachycrocuta sp. in Howelland Petter 1980); 29249, right mandibular ramusfragment with p4; 29280, proximal fragment of leftradius; 29290, right mandibular ramus fragmentwith p4, distal left radius fragment, right radiusshaft fragment; 29293, left distal radius fragment;29294, right mandibular ramus fragment with p2;29296, right mandibular ramus fragment with par-

tial alveolus for c, alveolus for p2, roots of p3, an-terior root of p4; 29297, left mandibular ramusfragment with roots of p4 and anterior root of m1;29299, proximal, shaft, and distal fragments ofright femur; 29301, left mandibular ramus frag-ment with p4 and anterior root of m1, separate p3;29302, left P4; 30229, right femur lacking distalend, proximal right tibia; 30234, associated partialleft forelimb with left ulna lacking olecranon, leftradius, left humerus lacking proximal articulation,left scapholunar, left magnum, left pisiform, left un-ciform; 30235, associated partial skeleton includingright mandibular ramus with i2 and c–m1 (Fig. 2B),left distal humerus fragment, right proximal anddistal humerus fragments, right radius (Figs. 3A–B),right calcaneum, right tibia lacking distal articula-tion, right ulna lacking distal articulation, frag-ments of the right and left scapulae, left cuboid,right and left navicular, right scapholunar, left lat-eral cuneiform, damaged right lateral cuneiform,right unciform, ?right patella, left MC II lackingdistal articulation, right MC II lacking proximal ar-ticulation, proximal part of right MC III, left andright MC V lacking proximal articulations, rightMC I, distal part of right MT II, right MT IV lack-ing proximal articulation, left and right MT V lack-ing proximal articulations, proximal, middle anddistal phalanges including proximal phalanx of dig-it 1 of the manus, pisiform, sternebrae, and cervi-cal, thoracic, lumbar, and caudal vertebral frag-ments; 30272, associated partial skeleton with rightmandible fragment with c, damaged p3, roots of p2and p4, left mandible fragment with roots of p2–p3, right maxilla fragment with C root, P1 alveolus,nearly complete P2, roots of P3, anterior root ofP4, left maxilla fragment with alveolus for I3, dam-aged C, roots of P1–P2, anterior root of P3, rightzygomatic, proximal end of right and left scapulae,fragment of distal right humerus shaft, right tibia,proximal, shaft and distal fragments of left tibia,pelvic fragment, left navicular, proximal fragmentof left MT V, tuber fragment of left calcaneum, par-tial distal right femur, proximal and distal frag-ments of left femur, fragment of left pisiform, prox-imal end of right MC III, pathological left MT II,distal end of left MT III, right MT III, proximalfragment of right and left MT IV, proximal end ofright MT V, proximal phalanx of left manus digit3, proximal phalanx of right manus digit 4, prox-imal phalanx of right manus digit 5, middle pha-lanx of right manus digit 4, middle phalanx of rightand left pes digit 4, middle phalanx of right andleft pes digit 5, sternebrae, fragments of cervical,thoracic, lumbar, and caudal vertebrae; 30306, leftdistal femur fragment; 30463, right mandibular ra-mus fragment with roots of p2–p4; 30482, associ-ated complete left MC III–V (Fig. 4); 30487, prox-imal part of left MT III; 30495, proximal fragmentof MT II; 30534, proximal right MT III; 30536,left p3; 30540, right I3; 30541, right lower canine;30544, left mandibular ramus fragment with p3and m1, p2 and p4 crowns separate; 31734, prox-


imal right ulna; 31735, proximal left ulna lackingolecranon; 32538, right m1; 32550, left P3; 32552,mandible fragments with associated left c and p3–m1; 32813, proximal right ulna fragment; 32822,left lower canine; 32865, postcranial fragments in-cluding a fragment of a proximal MC II, distal me-tapodials, a distal humerus fragment, and vertebralfragments.

MEASUREMENTS. See Tables 1 and 2The following is a composite description of the

material. The craniodental material shows limitedvariability, except in size, but where there is varia-tion, this is noted. There is limited duplication be-tween postcranial elements, which allows for a verylimited grasp of variation in the taxon, but doesmean that a significant proportion of the skeletonof Parahyaena howelli is actually known (Fig. 5).Some comparisons with representative morpholo-gies of extant Hyaena hyaena are made.

SKULL AND UPPER DENTITION. The skull isrepresented only by some very small fragmentsfrom KP 30272, which unfortunately are too smalland damaged to provide any information about themorphology of the species. This specimen has somevery damaged teeth and tooth roots that indicatethat the upper canine was slightly larger than thelower, that the P1 was small and single rooted, andthat P2 was considerably smaller than P3. All thesefeatures are normal in hyenas and the only fact ofinterest is the presence of P1. The I3 is representedby specimen KP 30540, which is worn, but showsthe distinctive derived hyaenid subcaniniform mor-phology of this tooth. The P3 is also representedby a damaged specimen, KP 32550. This toothprobably had a small anterolingual accessory cusp,though damage in this area makes this somewhatuncertain. The main cusp is high and conical, as istypical of derived hyenas, and the posterior acces-sory cusp is substantial, though precisely how largecannot be determined due to specimen damage. Thetooth is similar to P3 of modern Hyaena, but themain cusp is larger and stouter. The upper carnas-sial is represented by the isolated tooth KP 29302.It is typically hyaenid in morphology, with substan-tial parastyle and protocone, a large and relativelynarrow paracone and a long metastyle. The par-astyle is robust with a distinct anterior ridge leadingdown to an anterior cingulum with a hint of a pre-parastyle. The protocone is large but low and setin line with the anterior margin of the parastyle.The paracone is tall and trenchant and the metas-tyle long. There is a lingual cingulum that reachesfrom the posterior root of the protocone to the pos-terior quarter of the metastyle.

MANDIBLE AND LOWER DENTITION. Themandible and associated material are known fromsixteen specimens, most of which are fragmentaryand damaged, but include two nearly completerami, KP 10033 and KP 30235A (Figs. 2A–B). Themandible increases gradually in depth from anteri-or to posterior and is deepest just posterior to m1.Posterior to this point, the ventral margin of the

mandible rises in a shallow S shape to the angularprocess. The mandibular condyle is relatively slen-der in comparison with modern Hyaena and con-sists of two semidistinct areas, a lateral, higher oneand a medial, lower one. The latter does not tapermedially as is the case in Hyaena. The coronoidprocess is tall and slender compared with that ofmodern Hyaena, and has a distinct backward tilt.The anterior margin of the coronoid process issteeply S shaped. The masseteric fossa is deep andflat. The ventral part (insertion area for the M. mas-seter intermedius) is delimited by a strong ridge andis set distinctly lateral to the more dorsal parts ofthe masseteric fossa (insertion area for the M. mas-seter profundis). This is in contrast with the situa-tion in Hyaena, where the ridge separating thesetwo insertion areas is lower and less distinct andthe two areas are located in the same vertical plane.There is a single, large mental foramen situated be-neath p2. In KP 10033, the symphysis is brokenand all the incisors lost. The lower canine is brokenand chipped, but can be seen to have been a rela-tively robust tooth whose anteroposterior axis isangled relative to the main axis of the ramus. Thediastema is of about the same length as in Hyaena.The cheek tooth row curves gently to buccal fromp2 to p3, then curves gently back from p4 to m1,much as in modern Hyaena. Unlike the latter, how-ever, the p2 of KP 10033 is set at an angle to themain axis of the ramus.

The i2 is present only in KP 30235A. It is heavilyworn, but is clearly longer (anteroposteriorly) thanwide (mesiodistally). The tip is worn flat, thoughthe wear facet is angled from distal (higher) to me-sial. On the mesial side, the wear has reached theenamel–dentine juncture. The lingual face is alsoworn and there is an angle of about 708 betweenthe apical and buccal wear facets. The p2 is themost variable tooth in both size and shape. Thereis no anterior accessory cusp, but a small swellingat the anterior end of the tooth is present. The maincusp is narrow and conical, with slightly convexanterior and posterior margins. The posterior ac-cessory cusp is low and narrow. The posterior shelfof this tooth is variable in width. In KP 10033, itis narrow in comparison with modern Hyaena,which has a small shelf that is not present in thisKanapoi specimen. In KP 30235A and KP 30544,p2 is much broader posteriorly and more similar tothe condition in Hyaena. In KP 29296, the p2, asjudged from the alveolus, must have been notice-ably shorter than in the other specimens that pre-serve traces of this tooth. The p3 has no anterioraccessory cusp. Instead, the anterior margin of themain cusp is formed into a low crest that reachesthe anterior end of the tooth. The anterior and pos-terior margins of the robust, conical main cusp areslightly convex. The posterior accessory cusp is lowand round and set centrally in a posterior cingulumshelf. The tooth is variable in size and shape,though not to the extent seen in p2. KP 29301 hasa p3 that is nearly identical to that of KP 10033,


Figure 2 A, Parahyaena howelli, KP 10033, right mandibular ramus in (top to bottom) buccal, lingual, and occlusalview; B, Parahyaena howelli, KP 30235A, right mandibular ramus in (top to bottom) lingual, buccal, and occlusal view

whereas in KP 30235A and KP 30544, the p3 isnarrower and has a more distinct waist. KP 30536and KP 32552 are intermediate in morphology. Thetooth is broadly similar to p3 in Hyaena except forthe absence of an anterior accessory cusp. The p4

has a small, round anterior accessory cusp ap-pressed to a narrow, conical main cusp with moreor less straight anterior and posterior margins. Theposterior accessory cusp is relatively high and tren-chant. The posterolingual part of p4 has been dam-


Figure 2 Continued

aged and it is not possible to determine the widthof the posterior part of the tooth. The lower car-nassial is long and relatively low. The paraconid isslightly longer and wider than the protoconid. Themetaconid is very small but is distinctly developedand the talonid has two cusps, presumably the hy-poconid and entoconid. Compared with modern Hy-aena, the tooth is relatively much longer, the meta-conid smaller, and the talonid relatively shorter.

FORELIMB. The humerus is known from KP30235 (proximal and distal pieces) and KP 30234(shaft and distal articulation). The proximal frag-ment is too worn for detailed comparisons withHyaena, but is larger and appears relatively nar-rower. The distal articulation is transversely broad-er than in modern Hyaena, but is relatively moreslender anteroposteriorly. There is a large supra-trochlear foramen present in KP 30235.

The radius is known from KP 30235 (Figs. 3A–B)and KP 29280. It is in general very similar to thatof Hyaena, but is shorter for the same robusticity.The grooves for the extensor digitis communis, ex-tensor carpi radialis, and abductor pollicis longusare all more deeply incised than in Hyaena.

The ulna is known from several fragmentaryspecimens, KP 30234, KP 30235, KP 31734, KP31735, and KP 32813. The first two are the mostcomplete and indicate that the ulna of this taxonwas slightly shorter but more robust than that ofHyaena. The shaft is more rounded than in Hyae-na, the triceps groove is wider, the ridge on the cra-nial surface of the olecranon is narrower, the at-tachment area for the flexor carpi ulnaris is lessdistinct, and the pit beneath the radial notch is shal-lower. In addition, the rugosity for the articulationwith the radius begins more proximally on the


Figure 3 Parahyaena howelli, KP 30234, right radius in A, anterior and B, posterior view

shaft, while the groove for the abductor pollicislongus is much more distinct than in Hyaena.

Several of the carpals are known from differentspecimens. The scapholunar is known in specimensKP 30234 and KP 30235AC. It is slightly largerand more slender anteroposteriorly than that ofmodern H. hyaena. Specimen KP 30235AC is bro-ken on the medial side, but in KP 30234, it can beseen that the articular face for the radius extendsdown onto the medial rim, while in modern H. hy-aena, there is a much more distinct ridge limitingthe radial articulation to the dorsal side of thebone. This may indicate greater mobility of this ar-ticulation in the fossil form. In addition, the sulcus

for the flexor carpi radialis tendon is deeper andbounded medioventrally by a more prominent ridgethan in modern H. hyaena. The magnum is knownin KP 30234. It is shorter and wider than that ofmodern H. hyaena but is morphologically very sim-ilar in all other respects. The unciform is alsoknown from KP 30234. It is more robust than thatof modern H. hyaena and has a more open articularface for MC III. The pisiform is known from KP30234. It is larger than that of modern H. hyaena,but aside from size is practically indistinguishablefrom it.

All the metacarpals except MC II are knownfrom complete specimens. MC I, known from KP


Figure 4 Parahyaena howelli, KP 30482, associated leftMC III–V in dorsal view. Scale 5 50 mm

30235P, is a substantial element associated with atleast one phalanx. This is corroborated by KP39235V, which is tentatively identified as the prox-imal phalanx of the same digit. This phalanx bearsa large articular surface for an ungual phalanx,which has not been identified in the material. It isfar larger than that of any extant hyaenid, thoughrelatively smaller than its counterpart in Ikelohyae-na abronia Hendey, 1974, from Langebaanweg, aspecies that is otherwise smaller than the Kanapoiform. The second metacarpal is known from a dis-tal and a proximal fragment, KP 30235AH andAO, respectively. This metacarpal is more robustthan MC II in modern H. hyaena. Metacarpals IIIto V are associated in specimen KP 30482 (Fig. 4)and MC III is in addition known in KP 30235AGand KP 30235BH and in KP 30272. The thirdmetacarpal has larger proximal and distal articularsurfaces than MC III in modern H. hyaena, whilethe shaft is more robust but markedly shorter thanin the extant species. The plantar side of the prox-imal articular surface is narrower relative to thedorsal side than in the modern species. The fourthmetacarpal is, like the third, shorter and more ro-

bust than that of modern H. hyaena. The two spe-cies are similar in their MC IV morphology, but theproximal articulation in KP 30482 is somewhatmore triangular in shape, with a broader dorsal andnarrower plantar side than in the modern form.The fifth metacarpal is also more robust and short-er than that of modern H. hyaena, the differencebeing more accentuated in this element. The prox-imal articular surface with MC IV is set lessobliquely and more directly anteroposteriorly thanin modern H. hyaena and is also very wide com-pared with the condition in the modern species.

HINDLIMB. The femur is represented by vari-ous fragments from specimen KP 30272, includinga partial distal femur KP 30272N, proximal frag-ments of specimen KP 30229, distal fragments,specimen KP 30306, and proximal, shaft and distalfragments, KP 29299. These fragments suggest afemur that is somewhat larger and more robustthan the corresponding element in modern H. hy-aena, but otherwise do not show any distinguishingfeatures of note.

The tibia is known from fragments from the par-tial skeletons KP 30235D and KP 30272P, Q, aswell as from KP 30229. In general, the tibia is nota very diagnostic bone in Hyaenidae and this is truein the present case as well, the fossil specimens onlybeing distinguished from modern H. hyaena bytheir greater size and by the slightly greater devel-opment of the medial malleolus of KP 30272Q.

The navicular is known from KP 30235AE andAD, and KP 30272F. This bone is generally similarto that of modern H. hyaena, but is slightly larger.It differs in that the plantar process is wider thanhigh, the reverse of the condition in H. hyaena. Theprocess for the separation between the articulationwith the cuboid and the plantar side of the bone isless prominent than in H. hyaena.

The lateral cuneiform is known only from KP30235BJ and BP. It is larger than the correspondingbone in modern H. hyaena, apparently relativelymore so than other tarsals and carpals reportedhere. The proximal articular surface of the fossil ismore deeply indented laterally and medially than inH. hyaena and, in addition, the distal articular sur-face (for MT III) is concave in the fossil rather thanslightly convex as in H. hyaena.

The cuboid is known from KP 30235W. It is thetarsal that differs most from the corresponding el-ement in modern H. hyaena. The medial side of theproximal articular surface of the fossil has a medialextension that probably buttressed the medial partof the sulcus for the M. peritoneus longus tendon.This sulcus is shallow and nondescript in modernH. hyaena, deep and well developed in KP30235W. The cuboid of Crocuta crocuta (Erxleben,1777), on the other hand, is short and square witha deep, narrow sulcus.

The second metatarsal is known from KP 30495,30235AM, and 30272AB. The two former areproximal ends that are more robust than MT II inmodern H. hyaena but otherwise too worn for


Figure 5 Parahyaena howelli, known skeletal parts of P. howelli (gray) superimposed on a skeleton of a dog; skeletonadapted from Evans (1993)

meaningful comparisons to be made. The thirdspecimen, KP 30272, is pathological in that thebone appears to have been broken in life and sub-sequently healed. The distal end of this bone iscomposed of an amorphous mass of secondarybone suggestive of healing.

The third metatarsal is known from specimensKP 30272U and KP 30272AO, KP 30534, and KP30487. These specimens are more robust than thecorresponding element in modern H. hyaena, butare otherwise similar except for the proximodorsalarticular surface being concave rather than flat toconvex.

The fourth metatarsal is known from KP30235AF and KP 30272T and AC. It differs fromthat of H. hyaena only in its greater size and in theless expanded proximopalmar eminence.

The fifth metatarsal is known from KP 30235AKand AL and KP 30272AA and KP 30272AP. In thiscase, the greater size is the only clear differencefrom extant striped hyaena.

DISCUSSION. KP 10033 was recovered by theAmerican expeditions. It was referred to Hyaenasp. by Behrensmeyer (1976) and to Pachycrocutasp. by Howell and Petter (1980). The referral ofthis species to Parahyaena rests chiefly on thelength of the metastyle of P4. This is only knownfrom a single specimen, KP 29302, but can also beinferred from the length of the m1 trigonid in re-lation to p4 and m1 talonid length. The length of

the P4 metastyle is one feature that clearly distin-guishes all extant hyena species. Hyaena hyaenahas a short P4 metastyle, of about the length of theparacone or slightly shorter. In C. crocuta, the me-tastyle of P4 is exceptionally long and straight. InParahyaena brunnea, the metastyle of P4 is longerthan that of H. hyaena but shorter than that of C.crocuta. In the present case, the P4 metastyle hasthe relative length of that of P. brunnea. This con-trasts with the condition in Ikelohyaena abronia, apossible ancestor of H. hyaena (Hendey, 1978a;Werdelin and Solounias, 1991), in which the P4metastyle is short, as in its putative descendant. Noother features contradict assignment of the Kanapoihyena to Parahyaena, and rather than posit the ex-istence of a previously unknown hyaenid lineage, Iprefer to suggest a link to the living brown hyena.This represents the first direct indication of the an-cestry of the brown hyena, as all other known fossilParahyaena fit comfortably within the extant spe-cies (e.g., Hendey, 1974).

Family Felidae

Felids are common elements in the fossil faunas ofeastern Africa. Both Machairodontinae and Felinaeare present throughout the Plio–Pleistocene, but upto about 1.5 Ma, the former are by far the morecommon in the fossil record.


Tab

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Den

talm

easu

rem

ents

ofP

arah

yaen

aho

wel

lin.

sp.;

mea

sure

men

tpa

ram

eter

sas

inW

erde

linan

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loun

ias

(199

1)

KP1

0033

KP3

0235

KP3

0541

KP2

9290

KP2

9301

KP2

9249

KP3

0536

KP3

2538

KP3

2822

KP3

2552

KP3

2550

KP2

9302

ML

cW

cM

Lp2

Wp2

ML

p3

12.9

10.4

13.7 7.9

18.1

10.9 8.6

20.0

14.0

10.0

19.0

19.1

e15.

5e1

1.0

16.0

20.3

Wp3

ML

p4W

p4M

Lpp

4M

Lm

1

11.6

20.2

11.4

10.0

24.3

11.7

21.8

11.7

12.4

a25.

1

11.8

11.7

20.4

11.3

10.9

11.9

a11.

921

.312

.111

.424

.5W

m1

ML

tm1

ML

P3M

LP4

10.5

19.9

11.4

a20.

911

.8a2

1.3

11.0

19.8

a20.

434

.1W

aP4

Wbl

P4M

LpP

4M

Lm

P4

18.8 9.9

12.0

13.6

a5

appr

oxim

ate,

e5

esti

mat

ed


Table 2 Postcranial measurements of Parahyaena howelli n. sp.

KP30235 KP30234 KP29280 KP30482 KP30534 KP29293 KP32865

Humerus DistWRadius LRadius ProxW maxRadius ProxW minRadius DistW transv

46.6215.522.315.731.9

46.1

a21.416.0

32.4Radius DistW a–pMC II ProxW transvMC II ProxW a–pMC III LMC III ProxW transv

20.9

13.591.512.5

10.614.8

20.711.814.5

MC III ProxW a–pMC III DistW transv

14.8 15.2a14.3

MC III distW a–pMC IV LMC IV ProxW transvMC IV ProxW a–pMC IV DistW transv

11.589.312.214.613.6

MC IV DistW a–pMC V LMC V ProxW transvMC V ProxW a–pMC V DistW transvMC V DistW a–p

12.575.9

18.6 (14.0)15.6 (13.9)15.8 (12.9)

11.913.112.3

KP30272 KP29299 KP30229 KP30235

Femur HeadWFemur ProxW

24.351.4

24.7a53.3

Femur DistWTibia ProxWTibia DistWCalcaneus Head W transv

41.4

23.9

a42.444.0 43.7

14.4Calcaneus HeadW a–pCalcaneus tuber WmaxCalcaneus tuber WminCalcaneus SustW

20.520.411.024.3

KP30495 KP30487 KP30272

MT II ProxW transvMT II ProxW a–pMT III ProxW transvMT III ProxW a–p

a9.9a12.5

11.517.6

10.818.3

MT IV ProxW transvMT IV ProxW a–pMT V ProxW transvMT V ProxW a–p

9.816.58.2

13.1

Dinofelis Zdansky, 1924

Species of the genus Dinofelis are among the mostcommon Felidae in the fossil record of eastern Af-rica. The earliest record there and possibly the ear-liest anywhere is from Lothagam, where materialreferred to the genus is known from all members(Werdelin, 2003). The genus is subsequently pre-sent at most Plio–Pleistocene sites in eastern Africauntil its last occurrence at Kanam East (ca. 1.0 Ma;Werdelin and Lewis, 2001).

Dinofelis petteri Werdelin and Lewis, 2001(Figure 6)

KANAPOI MATERIAL. 30397, complete rightmandibular ramus with c–m1 (Fig. 6); 30542, distalleft ulna; ?30429, P4 metastyle.

MEASUREMENTS. KP 30397, Lc 5 13.9, Wc5 9.7, Lp3 5 13.1, Wp3 5 7.3, Lp4 5 20.6, Wp45 9.7, Lm1 5 23.2, Wm1 5 10.6. Measurementparameters defined in Werdelin and Solounias


Figure 6 Dinofelis petteri, KP 30397, right mandibular ramus in (top to bottom) buccal, lingual, and occlusal view

(1991). The horizontal ramus is low, but broad,with a noticeable thickening of the corpus. Thedepth is about the same throughout. The symphysisis deep and short and nearly vertically oriented,producing a small anteromedial chin. There are twomental foramina, one below the diastema between

the canine and p3 and one beneath the anteriorroot of p3. Both are set low on the ramus. Themasseteric fossa is deep and the masseteric foramenlarge, while the coronoid process is relatively shortanteroposteriorly. The condyle is thickest mediallyand tapers gradually toward the lateral end. The


Figure 7 Homotherium sp., KP 30420, right m1 in (top)buccal and (bottom) occlusal view

angular process is robust and angled ventrally rel-ative to the horizontal ramus.

The space for the incisors is very narrow, sug-gesting that they were either staggered or verysmall. The lower canine is short and robust andangled outward with respect to both the antero-posterior axis of the ramus and the sagittal plane.The diastema is long. The p3 has a small anterioraccessory cusp, a low, conical main cusp, and aposterior basin that forms the widest part of thetooth but lacks a posterior accessory cusp. The p4is long and slender. The anterior accessory cusp iswell developed and set far anteriorly, well awayfrom the main cusp. The main cusp is triangularwith straight anterior and posterior margins. Theposterior accessory cusp is similar in size to the an-terior but set closer to the main cusp. There is asmall posterior cingulum cusp and a low lingualcingulum crest, making the posterior basin the wid-est part of the tooth. The lower carnassial is typi-cally felid, with a broad paraconid and narrowerand somewhat longer protoconid. There is a mi-nute, posteriorly located talonid. The m1 is set ina groove at the posterior end of the horizontal ra-mus. This groove is bounded laterally by the mas-seteric fossa wall and medially by the root of theascending ramus.

The tip of the anconeal process of the ulna isbroken and the specimen is somewhat eroded. It isa relatively small, gracile bone compared with later,better known Dinofelis (see Werdelin and Lewis,2001 for a discussion).

DISCUSSION. This and other Dinofelis materialfrom Africa and other regions is described and ex-tensively discussed elsewhere (Werdelin and Lewis,2001). The Kanapoi material is referred to the spe-cies D. petteri, which is also known from a numberof other sites (Allia Bay, Laetoli, Hadar Sidi Hak-oma, and Denen Dora Members, Omo ShunguraMembers B–F, Koobi Fora Tulu Bor Member, WestTurkana Lomekwi Member) in eastern Africa. Thisgives the species a temporal range of ca. 4.2 Ma(Kanapoi) to 2.3 Ma (Shungura Member E/F).

Homotherium Fabrini, 1890

Material that can be referred to Homotherium isrelatively ubiquitous at eastern African Plio–Pleis-tocene sites. Unfortunately, much of this material isfragmentary or undescribed. Therefore, the taxon-omy of eastern African Homotherium is confused.Petter and Howell (1988) described a skull fromHadar as Homotherium hadarensis, noting its dif-ferences from Eurasian Homotherium. On the oth-er hand, Harris et al. (1988) described a skull fromWest Turkana, tentatively affiliating it with Hom-otherium problematicum (Collings et al., 1976).The latter comparison cannot be maintained, butneither does the West Turkana skull seem to belongto H. hadarensis. African Homotherium requiresrenewed investigation for the resolution of theseproblems.

Homotherium sp.(Figure 7)

KANAPOI MATERIAL. 30420, right m1 (Fig.7); 32558, complete right MC IV; 32820, completeproximal phalanx; 32882, proximal metatarsalfragment.

The lower carnassial is very long and slender.The paraconid is slightly broader than the proto-conid, but the latter is the longer of the two cusps.There is no metaconid and no talonid. The shaft ofMC IV is relatively straight and quite rounded incross-section, widest just below proximal articula-tion and gradually tapering distally. The distal ar-ticulation is about as tall as it is wide. The proximalphalanx is large and robust. The shaft is gentlyarched. The proximal articulation is broad and low,while the distal articulation is more nearly equal inheight and width, though the width is still some-what greater. Rugose surfaces are prominent on themedial and lateral sides of the shaft.

DISCUSSION. All of this material is clearly felidand is too large to represent any taxon other thanHomotherium. The m1 matches the lower carnas-sial of most other Homotherium in size and pro-portions, though it is distinctly smaller than m1


from a Homotherium mandible from Koobi Fora(KBS Member), as well as that of H. problemati-cum from Makapansgat. However, none of theKanapoi material can be considered diagnosticamong species of Homotherium and the materialmust be left as indeterminate species for the timebeing. The Kanapoi material represents the hithertooldest described material of Homotherium in east-ern Africa.

Felis Linnaeus, 1758

Fossils of the genus Felis are very rare in the fossilrecord of eastern Africa. In fact, aside from theKanapoi record, only a single specimen from theDenen Dora Member of the Hadar Formation canbe unequivocally referred to Felis sensu stricto (per-sonal observations).

Felis sp.

KANAPOI MATERIAL. 30546, fragments of P4of one or two individuals.

This material comes from a small feline, smallerthan ‘‘Felis small species’’ from Laetoli (Barry,1987). It is the size of the extant F. lybica Forster,1780. The main cusp is taller and shorter antero-posteriorly than in the Laetoli specimen.

DISCUSSION. Given the fragmentary nature ofthe material, as well as the almost complete lack ofknowledge of fossil African Felis at the presenttime, it is inadvisable to put a specific name to thismaterial.

Family Herpestidae

Apart from the notable exceptions of Laetoli andOlduvai, sites that have been excavated for micro-mammals, herpestids are rare in the fossil record ofeastern Africa. Because of the lack of screen-washed localities, it is not at present possible toestablish whether this is a sampling artifact, wheth-er it reflects a biased sample of localities vis-a-visenvironment, or whether it is a real phenomenon.

Helogale Gray, 1861

Dwarf mongooses are among the more commonherpestids in the Plio–Pleistocene of eastern Africa,with several species described from Laetoli and theShungura Formation (Wesselman, 1984; Petter,1987).

Helogale sp.

KANAPOI MATERIAL. 32826, fragments of aright mandibular ramus with broken p4, damagedm1, roots of m2; 31034, lower canine.

This material belongs to a very small carnivorespecies. The horizontal ramus is slender but rela-tively deep. In the carnassial, the paraconid is byfar the largest and tallest cusp, making up abouthalf of the trigonid in occlusal view. The protoco-nid is small and set buccally. The carnassial notchis relatively shallow. The metaconid is set directly

behind the paraconid and lingual to the protoconid.It is separated from both by shallow valleys. Thetalonid is low and short. The hypoconid is promi-nent, the entoconid less so. The m2 is single rooted,while the p4 is too damaged to provide any usefulmorphological information.

DISCUSSION. To the extent that comparisonscan be made, this material strongly resembles Hel-ogale species. It is a little larger than H. palaeogra-cilis (Dietrich, 1942) from Laetoli by the sameamount that that species is larger than the extantH. hirtula (Thomas, 1904). The Kanapoi materialclearly is not adequate for specific identification,and I prefer to leave it as Helogale sp. herein.

Family Viverridae

Viverrids are not uncommon in the Plio–Pleistoceneof eastern Africa, but very little of the material hasas yet been published. However, most of the ma-terial pertains to species larger than any living vi-verrid. Such species are found in three lineages, Viv-erra Linnaeus, 1758, with V. leakeyi Petter, 1963,known from a number of localities, Pseudocivetta,with the single species P. ingens Petter, 1973, ofuncertain affinities, and a third species from KoobiFora that may be related to Civettictis (Petter, 1963,1973; Hunt, 1996). Smaller viverrids are less com-mon, and almost none of the material has beenstudied.

Genetta Cuvier, 1816

Genetta sp. nov.(Figure 8)

Material that can be referred to Genetta is knownfrom a number of localities in the Plio–Pleistoceneof eastern Africa. Kanapoi is the oldest of these,though material referred to cf. Genetta (two spe-cies) is known from Lothagam (Werdelin, 2003).Younger localities with material of Genetta sp. in-clude Laetoli and the Shungura Formation, mem-bers B and C. The first record of the extant G. ge-netta (Linnaeus) is from the Upper Burgi Memberof the Koobi Fora Formation (personal observa-tions).

KANAPOI MATERIAL. 32565, left maxillafragment with posterior half of P3 and completeP4–M1; 32815, left mandibular ramus fragmentwith m1 and roots of p4 and m2 (Fig. 8); 30222,left lower canine.

The maxilla fragment represents a small carni-vore species. The P3 is damaged anteriorly. It hasa small but relatively tall posterior accessory cusp.The upper carnassial is elongated, with a small butsharp parastyle. The protocone is large and reachesfurther anteriorly than the parastyle. It is separatedfrom the paracone by a deep valley. The paraconeis large but short and pyramidal in shape. The me-tastyle is long and low, longer than the paracone.The M1 is broad but short and set at about 608 toP4. The parastyle wing is large and well developed,


Figure 8 Genetta n. sp., KP 32815, left mandibular ramusfragment in (top to bottom) buccal, lingual, and occlusalview

while the metastyle wing has been reduced. Boththe paracone and the metacone are present, withthe paracone being the larger of the two. The toothtapers gradually in length to the protocone, whichis the largest single cusp of the three cusps on M1.There is a deep basin between the paracone–meta-cone and protocone.

The horizontal ramus of the mandible is fairlythick and deep, becoming deeper but thinner at thelevel of the ascending ramus. The masseteric fossareaches to the posterior end of m1. The lower car-nassial has a trigonid with tall cusps and a short,narrow talonid. In occlusal view, the paraconid isthe largest cusp, but the protoconid is taller. Thelong axis of the paraconid is set at nearly right an-gles to the main axis of the tooth. The carnassialnotch is deep, while the notch separating the para-conid from the metaconid is shallower but wider.The paraconid–protoconid shearing blade is set atabout 458 to the main axis of the ramus. The pro-toconid is set buccally, overhanging the ramus tosome extent. The metaconid is set directly posteriorto the paraconid and lingual to the posterior endof the protoconid. It is separated from the proto-conid by a shallow transverse valley. The talonid isvery low and short compared to the trigonid. Thereare two distinct cusps, which can be homologizedwith the entoconid and hypoconid. The m2 wassmall and single rooted.

The lower canine KP 30222 is small and re-curved. The root is robust and relatively straight,though broken off part way down. The crownshows no accessory cusps or grooves.

DISCUSSION. The morphology of the teethreadily identify these specimens as belonging to thegenus Genetta. They are similar in size and mostfeatures to the extant G. genetta, but there are dif-ferences that indicate that the Kanapoi materialrepresents a separate species. These differences in-clude the less reduced protocone, broader P4 blade,and less reduced M1. These are all features inwhich the extant G. genetta is more derived thanthe Kanapoi form.

Carnivora Family Indet.

The following specimens have not been identifiedto family, mainly because of their incomplete na-ture. In view of the relative abundance of the spe-cies in the identified material, it seems likely thatmost, if not all, the material of ‘‘medium species’’should probably be referred to Parahyaena sp. nov.29289, distal metapodial fragment, medium spe-cies; 32827, proximal phalanx, medium species;32517, distal fragment of left? MC V?, small spe-cies (may not be carnivore); 32549, proximal me-tapodial fragment (may not be carnivore); 31738,distal metapodial fragment, medium species;32808, proximal phalanx, medium species; 32569,fragment of anterior premolar, possibly P1, mediumspecies; 32540, left lower canine, small species(possibly mustelid); 478, fragment of astragalus,large species (Machairodontinae indet. in Behrens-meyer 1976); 30478, vertebral fragments and distalmetapodial fragment, medium species; 30494, ver-tebral centrum; 32883, vertebral fragments includ-ing dens of axis, medium species; 30432, distalright humerus condyle; 29291, fragment of distalleft femur; 30469, fragment of proximal left femur;29298, right upper canine.

SUMMARY

The Kanapoi carnivore fauna, with its eight speciesin as many genera, representing five families, is asubstantial addition to the early Pliocene record ofCarnivora in Africa. It shares a number of generaand species with other African early–middle Plio-cene localities, such as Langebaanweg and Laetoli,but overall has a unique mixture of species. Simi-larities with Langebaanweg, which is somewhatolder and relatively distant, are at the generic level(Enhydriodon, Dinofelis, Homotherium), whilesimilarities with Laetoli, which is closer both in ageand geography, lie at the species level (Parahyaenahowelli, D. petteri). The small number of taxa fromthe Apak Member at Lothagam makes compari-sons with that site difficult.

On the other hand, differences between Lange-baanweg and Kanapoi show that the former stillincludes Miocene relicts (taxa such as HyaenictisGaudrey, 1861, Plesiogulo Zdansky, 1924, and


Machairodus Kaup, 1833), while the latter is moretypically Pliocene and lacks these Miocene forms.

The Nawata Formation at Lothagam includes anumber of forms whose affinities lie outside Africa(mostly in western Eurasia, but also on the Indiansubcontinent). The Kanapoi fauna, on the otherhand, includes only forms whose immediate fore-bears can be found in Africa. Thus, the Kanapoifauna represents the currently best-known evidencefor the first post-Miocene radiation of endemic Af-rican Carnivora.

ACKNOWLEDGMENTS

I would like to express my thanks to the government ofthe Republic of Kenya and to the National Museums ofKenya for allowing me to carry out this study. My thanksalso to M.G. Leakey for her invitation to work on theKanapoi material, to M.E. Lewis for discussions, to themany curators who have allowed me to study comparativematerial in their care, and to all the field crew and mu-seum staff of the Department of Palaeontology, NationalMuseums of Kenya, without whose efforts there would beno material to study. Inger Wikman-Backstrom made thespecimen drawings. This work was financed by the Swed-ish Science Council.

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NUMBER 49824 DECEMBER 2003

GEOLOGY AND VERTEBRATE PALEONTOLOGY

OF THE EARLY PLIOCENE SITE OF KANAPOI,

NORTHERN KENYA

EDITED BY JOHN M. HARRIS AND MEAVE G. LEAKEY

900 Exposition BoulevardLos Angeles, California 90007

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