Was australopithecus anamensis ancestral to A. afarensis?

114
C. V. Ward Departments of Anthropology and Pathology and Anatomical Sciences, 107 Swallow Hall, University of Missouri, Columbia, Missouri 65211, U.S.A. E-mail: [email protected] M. G. Leakey Division of Palaeontology, National Museums of Kenya, P.O. Box 40658, Nairobi, Kenya. E-mail: [email protected] A. Walker Departments of Anthropology and Biology, Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A. E-mail: [email protected] Received 6 March 2001 Revision received 25 June 2001 and accepted 27 June 2001 Keywords: Australopithecus anamensis, Kanapoi, Allia Bay, description, morphology. Morphology of Australopithecus anamensis from Kanapoi and Allia Bay, Kenya The hominid species Australopithecus anamensis was originally described in 1995, with new specimens and more secure dates given in 1998. This paper lists all fossils attributed to A. anamensis, and provides anatomical descriptions of those not yet described in detail with photographs of all but undiagnostic fragments. We also provide comparative analysis of these specimens. The A. anamensis holotype mandible was found at Kanapoi, as were most of the paratypes. The Allia Bay sample is less well represented, and does not preserve many anatomical elements diagnostic of this species. Still, the Allia Bay sample most closely resembles that from Kanapoi, and we suggest that for the time being it be retained as A. anamensis. A. anamensis most closely resembles A. afarensis, but can be distinguished from it in many features. Most of these features are inferred to be primitive for the genus. Based on the limited postcranial evidence available, A. anamensis appears to have been habitually bipedal, although it retained some primitive features of its upper limbs. A. anamensis differs from A. afarensis in having narrower, more parallel jaws with a very slightly more ape-like canine/premolar complex than is found in A. afarensis, although not as ape-like as in Ardipithecus ramidus. It had slightly larger lower lateral incisors, a unique upper canine mor- phology, and a different structure of the lateral nasal aperture than A. afarensis. A. anamensis had at least as great a range of body size, and perhaps slightly greater canine dimorphism, although this is difficult to determine. At present, there appears to be no autapomorphies precluding A. anamensis from ancestry of A. afarensis. 2001 Academic Press Journal of Human Evolution (2001) 41, 255–368 doi:10.1006/jhev.2001.0507 Available online at http://www.idealibrary.com on Introduction The holotype and paratype series of Australopithecus anamensis were found at Kanapoi, Kenya. Other fossils attributed to A. anamensis have been found at Allia Bay, Kenya. This species was first described in Leakey et al. (1995). Additional specimens and more secure dates were given three years later (Leakey et al., 1998). All fossils attributed to A. anamensis date to between 3·9 and 4·2 Ma. The older of the two sites is the type site of Kanapoi. With the exception of one specimen, a mandible (KNM-KP 29287), all Kanapoi hominins come from strata dated to between 4·17 0·03 and 4·07 0·03 Ma (Leakey et al., 1998). The mandible KNM-KP 29287 derives from the paleosol developed on the upper tuff, and therefore cannot be much younger. The Allia Bay fossils are slightly younger than those from Kanapoi. At Allia Bay, most of the hominids were found at the 261-1 site. This site lies just below the Moiti Tuff, dated elsewhere in the region to 3·94 0·03 Ma (Leakey et al., 1995). White et al. (1993) report an age of 3·89 0·02 for tuff VT-1 in the Maka area of Ethiopia, a tuff that on chemical grounds is regarded as 0047–2484/01/100255+114$35.00/0 2001 Academic Press

description

articulo que discute las relaciones filogeneticas entre dos especies de australopitecinos

Transcript of Was australopithecus anamensis ancestral to A. afarensis?

  • C. V. WardDepartments of Anthropologyand Pathology andAnatomical Sciences,107 Swallow Hall,University of Missouri,Columbia, Missouri 65211,U.S.A. E-mail:[email protected]

    M. G. LeakeyDivision of Palaeontology,National Museums of Kenya,P.O. Box 40658, Nairobi,Kenya. E-mail:[email protected]

    A. WalkerDepartments ofAnthropology and Biology,Pennsylvania StateUniversity, University Park,Pennsylvania 16802, U.S.A.E-mail: [email protected]

    Received 6 March 2001Revision received25 June 2001 andaccepted 27 June 2001

    Keywords: Australopithecusanamensis, Kanapoi,Allia Bay, description,morphology.

    Morphology of Australopithecus anamensisfrom Kanapoi and Allia Bay, Kenya

    The hominid species Australopithecus anamensis was originallydescribed in 1995, with new specimens and more secure dates givenin 1998. This paper lists all fossils attributed to A. anamensis, andprovides anatomical descriptions of those not yet described in detailwith photographs of all but undiagnostic fragments. We also providecomparative analysis of these specimens. The A. anamensis holotypemandible was found at Kanapoi, as were most of the paratypes. TheAllia Bay sample is less well represented, and does not preserve manyanatomical elements diagnostic of this species. Still, the Allia Baysample most closely resembles that from Kanapoi, and we suggestthat for the time being it be retained as A. anamensis. A. anamensismost closely resembles A. afarensis, but can be distinguished from itin many features. Most of these features are inferred to be primitivefor the genus. Based on the limited postcranial evidence available,A. anamensis appears to have been habitually bipedal, although itretained some primitive features of its upper limbs. A. anamensisdiffers from A. afarensis in having narrower, more parallel jaws with avery slightly more ape-like canine/premolar complex than is found inA. afarensis, although not as ape-like as in Ardipithecus ramidus. It hadslightly larger lower lateral incisors, a unique upper canine mor-phology, and a different structure of the lateral nasal aperture than A.afarensis. A. anamensis had at least as great a range of body size, andperhaps slightly greater canine dimorphism, although this is difficultto determine. At present, there appears to be no autapomorphiesprecluding A. anamensis from ancestry of A. afarensis.

    2001 Academic Press

    Journal of Human Evolution (2001) 41, 255368doi:10.1006/jhev.2001.0507Available online at http://www.idealibrary.com on

    Introduction

    The holotype and paratype series ofAustralopithecus anamensis were found atKanapoi, Kenya. Other fossils attributed toA. anamensis have been found at Allia Bay,Kenya. This species was first described inLeakey et al. (1995). Additional specimensand more secure dates were given threeyears later (Leakey et al., 1998).

    All fossils attributed to A. anamensis dateto between 39 and 42 Ma. The older of thetwo sites is the type site of Kanapoi. Withthe exception of one specimen, a mandible(KNM-KP 29287), all Kanapoi hominins

    00472484/01/100255+114$35.00/0

    come from strata dated to between417003 and 407003 Ma (Leakeyet al., 1998). The mandible KNM-KP29287 derives from the paleosol developedon the upper tuff, and therefore cannot bemuch younger.

    The Allia Bay fossils are slightly youngerthan those from Kanapoi. At Allia Bay, mostof the hominids were found at the 261-1site. This site lies just below the MoitiTuff, dated elsewhere in the region to394003 Ma (Leakey et al., 1995). Whiteet al. (1993) report an age of 389002 fortuff VT-1 in the Maka area of Ethiopia, atuff that on chemical grounds is regarded as

    2001 Academic Press

  • 256 . . ET AL.

    Specimens attributed to Australopithecus anamensis

    Specimen number Figure Element

    KanapoiKNM-KP 271 13 L distal humerusKNM-KP 29281 1, 2 Holotype mandible & L temporal fragmentKNM-KP 29282 LM1 or M2KNM-KP 29283 3 MaxillaKNM-KP 29284 4 RC & RP3 germsKNM-KP 29285 14, 15 R proximal & distal tibiaKNM-KP 29286 5 Mandible fragments & associated dentition

    (RI1, L & RI2-M3)KNM-KP 29287 6 Mandible with teethKNM-KP 30498 7 L & R maxillary fragments & associated dentitionKNM-KP 30500 8 Mandibular fragments & associated dentitionKNM-KP 30502 4 Associated mandibular tooth fragmentsKNM-KP 30503 16 Proximal manual phalanxKNM-KP 30505 4 Partial M germKNM-KP 30942 5 tooth fragmentsKNM-KP 31712 9 Associated juvenile mandibular & dental fragmentsKNM-KP 31713 10 R mandible with tooth fragmentsKNM-KP 31714 4 Ldm2KNM-KP 31715 LM1 or M2 fragment & two other tooth fragmentsKNM-KP 31716 P3 or P4 fragment & C/ fragmentsKNM-KP 31717 4 LM3, RM3 & LM2 fragmentsKNM-KP 31718 R Mandibular fragment (M23)KNM-KP 31719 I1

    KNM-KP 31720 Maxillary M fragmentKNM-KP 31721 RM2 & M3 partial crownsKNM-KP 31723 4 RM3

    KNM-KP 31724 17 L capitateKNM-KP 31726 4 RP4

    KNM-KP 31727 RCKNM-KP 31728 4 LM1KNM-KP 31729 4 Rdm2KNM-KP 31730 4 LM2 & RP3KNM-KP 31732 Tooth fragmentsKNM-KP 34725 11 Associated juvenile dentition and skull fragmentsKNM-KP 35838 LM3KNM KP 35839 12 Associated LI1, RC & LP3

    KNM-KP 35840 LM3 & maxillary M fragmentsKNM-KP 35841 M crownKNM-KP 35842 4 R maxillary MKNM-KP 35844 M fragmentKNM-KP 35845 M fragmentKNM-KP 35847 4 LM2KNM-KP 35850 Maxillary M fragmentKNM-KP 35851 LM2 or M3 fragmentKNM-KP 35852 4 LC

    KNM-KP 37522 L mandibular molarKNM-KP 37523 M fragmentKNM-KP 37524 Tooth fragments

    Allia BayKNM-ER 7727 LM2

    KNM-ER 20419 22 L radiusKNM-ER 20420 LM2

    KNM-ER 20421 RM3

    Table 1

  • 257AUSTRALOPITHECUS ANAMENSIS

    Continued

    Specimen number Figure Element

    Allia Bay (Continued)KNM-ER 20422 LM1KNM-ER 20423 LM2KNM-ER 20427 LM1

    KNM-ER 20428 LM3KNM-ER 20432 L mandibular fragment (P34)KNM-ER 22683 LP4KNM-ER 24148 Ldm2

    KNM-ER 30200 18 L maxillary fragment (M12, partial M3)KNM-ER 30201 19 LM1KNM-ER 30202 19 RIl

    KNM-ER 30731 19 RCKNM-ER 30744 RC

    KNM-ER 30745 20 L maxillary fragment (partial C, P3M1, partial M2, M3)KNM-ER 30747 LP4KNM-ER 30748 L maxillary M fragmentKNM-ER 30749 19 LM1KNM-ER 30750 RCKNM-ER 35228 21 RP4KNM-ER 35229 L mandibular M fragmentKNM-ER 35230 M fragmentKNM-ER 35231 19 RM1 or M2

    KNM-ER 35232 19 LM1KNM-ER 35233 19 LM2KNM-ER 25234 LP3KNM-ER 35235 19 LM2

    KNM-ER 35236 19 LM3

    KNM-ER 35238 19 RM1

    Table 1

    a correlative of the Moiti Tuff. The ageof the bone bed bearing the majority ofhominin fossils can be extrapolated tohave been 395005 Ma (C. S. Feibel,personal communication). KNM-ER30200, KNM-ER 30201, KNM-ER 30744were found about 1 km to the east of the261-1 site in a small drainage channel thatcut through the Moiti Tuff. The strata atSibilot, near site 261-1, yielded a homininradius attributed on the basis of age toA. anamensis, and is estimated to be3901 Ma (Heinrich et al., 1993).

    The paleoenvironmental reconstructionsfor Kanapoi and Allia Bay have been men-tioned in Coffing et al. (1994), Leakey et al.(1995), Ward et al. (1999b), and Wynn(2000). As far as can be determined, thehabitats sampled at these sites were similarto those described for A. afarensis at Hadar,

    Ethiopia, and Laetoli, Tanzania; fairlywooded regions that included woodland andbushland, sometimes with edaphic grasslandand often well watered (Reed, 1997). Theydiffer from the more closed woodland habi-tats reconstructed for the earlier Ardipithecusramidus site of Aramis, Ethiopia (Wolde-Gabriel et al., 1994). In one respect, Wynns(2000) conclusion, based on paleosols andtheir carbon isotopes, is slightly at variancewith the australopithecine habitats inter-preted by Reed (1997). The hominin fossilsat Kanapoi are associated with soils charac-teristic of semi-arid vegetational mosaics.Wynn (2000) suggests that this indicatesthat the hominins thrived in mosaic settings,whereas Reed (1997) concludes that theenvironment in which these Australopithecusspp. existed was fairly static and con-strained by minimum and maximum

  • 258 . . ET AL.

    Description of Fossils

    Each fossil is described first without specificcomparative references to provide an inven-tory of the preservation and morphology ofeach. Descriptions are provided by site,separated into craniodental and postcranialsections. Specimens are described innumeric order within these sections. Allspecimens that have been attributed to A.anamensis are listed by anatomical elementin Table 1.

    Measurements are given in millimetersunless otherwise indicated. Standard metricdata are listed in Tables 2, 3 & 4, and otherdata are included in the text. Dentalmeasurements we previously reported(Leakey et al., 1995; Leakey et al., 1998)were taken following Wood (1991). Dentaldata published for A. afarensis, however,were taken using different techniques(White, 1977) that yield slightly differ-ent results. To permit metric comparisonwith other East African Australopithecusspecimens, tooth measurements reported(Table 2) in this paper were taken followingWhite (1977). These data should be con-sidered the definitive metric sample forcomparative purposes.

    Anatomical terminology follows Johansonet al. (1982). Abbreviations used in thetext and tables are as follows (most followJohanson et al., 1982):

    AP= anteroposterior/lyML= mediolateral/ly

    SI= superoinferior/lyMD= mesiodistal/lyBL= buccolingual/ly

    LaL= labiolingual/lyPD= proximodistal/lyDP= dorsopalmar/lyPrd= protoconid

    Med= metaconidHyd= hypoconidEnd= entoconidHld= hypoconulid

    Pa= paraconePr= protocone

    Me= metaconeHy= hypoconeFa= anterior foveaFc= central foveaFp= posterior foveaC6= tuberculum sextum

    Mmr= mesial marginal ridgeDmr= distal marginal ridgeMlg= median longitudinal grooveCo= crista obliqua

    IPF= interproximal wear facetL= leftR= right

    Kanapoi

    At Kanapoi, specimens that were found inclose proximity and that appeared to repre-sent a single individual were given oneaccession number. Many of these have morethan one field number. Other specimensthat share a field number may representmore than one individual and therefore havedifferent accesssion numbers. If fragmentsthat make up a specimen cannot be certainlyassociated, different accession numbers havebeen assigned. In cases where more than one

    amounts of rainfall and tree cover. Wecannot be absolutely sure of the specifichabitats favored by the Kanapoi hominins,however, because most of the hominin fos-sils show signs of carnivore damage, andthere might be a depositional bias caused bythe behavioral proclivities of the predatorsand/or scavengers, rather than of thehominins.

    Preliminary reports of the A. anamensisfossils are found in the original publications,and Leakey & Walker (1997) and Wardet al. (1999b). This paper describes themorphology of these fossils in detail, putsthe collection in comparative context, andmakes some functional and evolutionaryinterpretations.

  • 259AUSTRALOPITHECUS ANAMENSIS

    Tab

    le2

    Den

    tal

    met

    rics

    for

    Au

    stra

    lop

    ith

    ecu

    san

    amen

    sis

    Spe

    cim

    enS

    ide

    I1C

    P3

    P4

    M1

    M2

    M3

    MD

    LaL

    MD

    LaL

    MD

    BL

    MD

    BL

    MD

    BL

    ant

    BL

    post

    MD

    BL

    ant

    BL

    post

    MD

    BL

    Max

    illar

    ype

    rman

    ent

    dent

    itio

    nK

    NM

    -ER

    7727

    L12

    314

    714

    3K

    NM

    -ER

    2042

    0R

    163

    KN

    M-E

    R20

    421

    R11

    213

    7K

    NM

    -ER

    2042

    2L

    119

    109

    KN

    M-E

    R20

    428

    L15

    713

    7K

    NM

    -ER

    3020

    0R

    103

    117

    113

    114

    132

    116

    KN

    M-E

    R30

    202

    R10

    5a

    93

    KN

    M-E

    R30

    744

    L(7

    8)

    (90

    )K

    NM

    -ER

    3074

    5L

    (11

    0)9

    913

    08

    813

    912

    214

    113

    9(1

    32)

    127

    (14

    5)K

    NM

    -ER

    3523

    1R

    117

    125

    119

    KN

    M-E

    R35

    232

    L12

    9(1

    22)

    KN

    M-E

    R35

    235

    R(1

    29)

    KN

    M-E

    R35

    236

    L11

    513

    0K

    NM

    -ER

    3523

    8R

    (10

    0)12

    812

    3K

    NM

    -KP

    2928

    3L

    (93

    )12

    17

    5[7

    8]

    (12

    8)12

    914

    713

    313

    014

    7K

    NM

    -KP

    2928

    3R

    79

    [81

    ]11

    3[1

    19]

    132

    122

    132

    148

    133

    KN

    M-K

    P30

    498

    L10

    98

    2K

    NM

    -KP

    3049

    8R

    (10

    6)10

    28

    713

    211

    613

    912

    611

    6K

    NM

    -KP

    3171

    7L

    111

    138

    KN

    M-K

    P31

    723

    R(1

    27)

    (15

    7)K

    NM

    -KP

    3172

    6L

    72

    KN

    M-K

    P34

    725

    R14

    214

    9K

    NM

    -KP

    3583

    9L

    124

    89

    118

    KN

    M-K

    P35

    839

    R11

    711

    2K

    NM

    -KP

    3584

    2R

    116

    KN

    M-K

    P35

    852

    L(1

    10)

    (10

    1)

  • 260 . . ET AL.

    Tab

    le2

    Con

    tin

    ued

    Spe

    cim

    enS

    ide

    I 1I 2

    CP

    3P

    4M

    1M

    2M

    3

    MD

    LaL

    MD

    LaL

    MD

    LaL

    MA

    XM

    INM

    DB

    LM

    DB

    LM

    DB

    LM

    DB

    L

    Man

    dibu

    lar

    perm

    anen

    tde

    ntit

    ion

    KN

    M-E

    R20

    423

    L12

    3K

    NM

    -ER

    2043

    2L

    120

    86

    97

    119

    KN

    M-E

    R22

    683

    L8

    7[9

    2]

    104

    KN

    M-E

    R30

    201

    L11

    610

    2K

    NM

    -ER

    3073

    1R

    83

    106

    KN

    M-E

    R30

    750

    R6

    69

    2K

    NM

    -ER

    3522

    8R

    74

    96

    KN

    M-E

    R35

    233

    L14

    813

    313

    0K

    NM

    -KP

    2928

    1L

    59

    [66

    ]7

    56

    5[7

    5]

    86

    88

    96

    117

    85

    79

    [82

    ]9

    811

    9[1

    27]

    119

    134

    [13

    7]12

    614

    412

    2K

    NM

    -KP

    2928

    1R

    61

    [69

    ]7

    36

    9[7

    8]

    86

    87

    94

    115

    87

    78

    [84

    ]10

    312

    0[1

    26]

    120

    135

    [13

    9]12

    614

    311

    9K

    NM

    -KP

    2928

    4R

    98

    114

    (11

    3)(8

    6)

    KN

    M-K

    P29

    286

    L7

    3[8

    7]

    78

    104

    124

    94

    95

    113

    123

    119

    138

    143

    132

    KN

    M-K

    P29

    286

    R8

    010

    311

    212

    39

    19

    511

    712

    311

    814

    514

    014

    113

    4K

    NM

    -KP

    2928

    7L

    68

    86

    85

    98

    114

    136

    128

    136

    KN

    M-K

    P29

    287

    R8

    210

    3(1

    42)

    131

    KN

    M-K

    P30

    500

    L13

    48

    913

    313

    515

    815

    1K

    NM

    -KP

    3050

    0R

    138

    131

    159

    147

    170

    134

    KN

    M-K

    P31

    712

    L6

    612

    110

    5K

    NM

    -KP

    3171

    2R

    115

    105

    KN

    M-K

    P31

    717

    R13

    712

    4K

    NM

    -KP

    3173

    0L

    (10

    0)K

    NM

    -KP

    3472

    5L

    73

    85

    121

    137

    122

    130

    140

    KN

    M-K

    P35

    847

    L13

    6

  • 261AUSTRALOPITHECUS ANAMENSIS

    Tab

    le2

    Con

    tin

    ued

    Spe

    cim

    enS

    ide

    di2

    MD

    LaL

    Dec

    iduo

    usm

    axill

    ary

    dent

    itio

    nK

    NM

    -KP

    3472

    5R

    (45

    )(4

    0)

    Spe

    cim

    enS

    ide

    dcdm

    1dm

    2

    MD

    LaL

    MD

    BL

    MD

    BL

    Dec

    iduo

    usm

    andi

    bula

    rde

    ntit

    ion

    KN

    M-K

    P31

    712

    100

    79

    KN

    M-K

    P31

    729

    (97

    )7

    9K

    NM

    -KP

    3472

    5R

    68

    (55

    )K

    NM

    -KP

    3472

    5L

    (67

    )5

    6(9

    3)

    (67

    )

    Mea

    sure

    men

    tsm

    ainl

    yfo

    llow

    Whi

    te(1

    977)

    ,exc

    ept

    teet

    har

    em

    easu

    red

    aspr

    eser

    ved

    wit

    hco

    rrec

    tion

    sfo

    rin

    ters

    titi

    alw

    ear

    give

    nin

    [],

    and

    BL

    dim

    ensi

    ons

    for

    M1

    and

    M2

    give

    nac

    ross

    mes

    ial

    and

    dist

    alcu

    sps

    inde

    pend

    entl

    y.A

    llm

    easu

    rem

    ents

    give

    nin

    mm

    .(

    )=va

    lue

    esti

    mat

    eddu

    eto

    dam

    age.

    a=to

    oth

    mea

    sure

    das

    pres

    erve

    dde

    spit

    ein

    ters

    titi

    alw

    ear;

    esti

    mat

    ing

    orig

    inal

    dim

    ensi

    onre

    liabl

    yis

    not

    poss

    ible

    .

  • 262 . . ET AL.

    individual has been recovered from a site, anote is given at the beginning of the speci-men description with possible associationsindicated. A map showing the relationshipof several of the hominin discoveries foundclose to the type mandible is given in Wynn(2000, Figure 2).

    Table 3 Mandibular metrics for Australopithecus anamensis*

    KNM-KP 29281 KNM-KP 29287 KNM-ER 31713

    Minimum breadth between crownsP3 259 P4 281 M1 264 M2 268

    Breadth between crown centersP3 359 P4 372 M1 376 M2 386

    Symphysis dimensionsSI height 270 270 270AP length 322 380 290Maximum length 410 420 338Minimum breadth 210 195 177Angle to alveolar margin 141 135 142

    Left Right Left Right Right

    Corpus dimensions at P4/M1 junctionSI height 340 340 423 290ML breadth 196 185 225 197Minimum breadth 179 177 197 178

    Height of mental foramen centerFrom alveolar margin 18 19 20 23 From base of mandible 16 22 17

    Mental foramen SI height 22 28 26 Mental foramen AP length 41 33 46

    *Mandibular metrics follow Wood (1991).

    Craniodental FossilsKNM-KP 29281Holotype mandibleand temporal fragment (Figures 1 and 2).The two pieces of this specimen were foundonly a few centimetres apart and are there-fore included under one accession numberas a single individual.

    A: Holotype mandible (L and RI1M3)

    Preservation. This adult mandible consistsof most of the body with all the permanentteeth, which are complete except for someminor damage. It is missing its rami, angles,and the base posterior to M1. The left andright sides of the body are separated by alarge crack, and the two halves do not matchperfectly. There are several puncture markson the lateral and medial surfaces of thebody, probably carnivore tooth marks. Sev-eral cracks are probably weathering damagecaused as the mandible dried on a landsurface. Minor distortion is caused by cracksthat have opened throughout the body. Theincisors and canines are hinged anteriorly intheir alveoli, particularly on the left side, andmatrix has filled in the gaps posterior to

  • 263AUSTRALOPITHECUS ANAMENSIS

    Table 4 Metrics for new Australopithecus anamensis postcranial elements

    Tibia KNM-KP 29285 Phalanx KNM-KP 30503

    Proximal Maximum fragment length 329Maximum fragment length 103 Midshaft DP depth 70Plateau maximum ML (70) Midshaft ML breadth 97Plateau maximum AP (46) Distance from flexor ridges from

    proximal joint surface center24

    Medial condyle AP (45) Proximal end DP depth (9)Medial condyle ML (27) Proximal end ML breadth 127Lateral condyle AP ((37))Lateral condyle ML ((26))Minumum intercondylar distance 16Plateau to distalmost point on tuberosity 31Maximum shaft breadth at break 33Minimum shaft breadth at break 21Semimembranosus m. insertion site SI 15Semimembranosus m. insertion site ML 18

    DistalCapitate KNM-KP 31724

    Maximum fragment length 96 PD length 218AP shaft breadth at break 22 DP depth (148)ML shaft breadth at break 22 ML width of head (125)Maximum AP depth metaphysis 33Maximum ML breadth metaphysis 43AP depth of talar facet 24ML width of talar facet at center 26ML width of talar facet at lateral edge 13ML width of talar facet at medial edge 21SI length of malleolus 14Maximum AP depth of malleolus 13SI height of fibular facet 7AP depth of fibular facet (16)Width of flexor m. groove 8

    ( ) indicates estimate, (( )) more tentative estimate.

    them. The left I1 and I2 have shiftedanteriorly by about 43, the right I1 by a littleless, and the right I2 by only a little. The leftincisors have also rotated slightly laterally.The right /C has shifted forward for 20, theleft /C by 39. The true positions can befound by realignment of casts of the teethusing the IPFs as a guide. The labial sides ofthe incisor and canine alveoli are broken off,as is a piece on the inferior side of thesymphysis. In posterior view, it is apparentthat the left M3 is in a piece of the body thathas been rotated slightly clockwise a fewdegrees.

    Lateral aspect. The tooth rows show a mildheliocoidal occlusal wear plane and a weak

    Curve of Spee. The alveolar margin isstraight and parallels the occlusal marginwhere it is preserved. Although the rami aremissing, in places a narrow extramolarsulcus is visible. A mild jugum for P4 and aslightly larger one for the mesiobuccal P3root interrupt the body surface. The caninejuga are missing, but would have formedrounded anterolateral corners to the man-dibular body.

    The lateral superior torus is merely theextension of the oblique line for the attach-ment of the buccinator muscle, and existsonly as a rounded eminence that disappearsbelow M1. A narrow marginal torus runsanteriorly, passing just inferior to the mental

  • 264 . . ET AL.

    Figure 1. Holotype mandible, KNM-KP 29281A. Top row, occlusal and basal views; middle row, rightand left lateral views; bottom row, right and left medial views.

    foramen and fades out below P3. It is separ-ated from the base by a shallow groove.Anterior to the lateral torus and above the

    marginal torus is a broad, shallow intertoralsulcus centered superior and anterior to themental foramen. There is a single mental

  • 265AUSTRALOPITHECUS ANAMENSIS

    foramen on each side. Each is centeredbetween P4 and M1 directly above the baseof the symphysis, 175 down from thealveolar margin on the left and 192 on theright. They open anteriorly. The left one hasabraded margins, but the right one measures35 AP by 26 SI. The mental surfaceis strongly but smoothly convex in bothdirections.

    Posterior aspect. The postincisive planum isabout 24 long, reaching posteriorly as far asthe level of the P4s and is concave in bothdirections. It ends in a strong superior trans-verse torus, which swings laterally from themidline to merge into the medial body wallat the level of the junction between M1 andM2. There is an even stronger inferiortransverse torus centered 16 inferiorly andposteriorly from the superior one, and separ-ated from it by a marked genial fossa. Theinferior torus reaches as far posteriorly as themesial edge of the M1s at midline, con-tinuing almost directly laterally to mergewith the body also level with the M1s. Thereare faint digastric impressions on the under-side of the inferior torus on each side, whichmeet in the midline to form a crest in thecenter of the torus.

    Medial aspect. The symphyseal cross-section is strongly inclined, slopingposteriorly with its long axis running 141to the alveolar margin. The entire externalcontour is smoothly convex through itsrounded inferior margin, with no flatteningevident basally. The alveolar margins arestraight. The alveolar torus is mild through-out its length except below M3, where itbecomes more prominent. The alveolartorus is only about 15 SI here, but deepensanteriorly to merge with the superior trans-verse torus. Inferior to the alveolar torus, thesubalveolar fossa is deepest posteriorlybecoming shallow anteriorly, where its in-ferior edge swings up and over the inferiortransverse torus allowing it to blend into thegenioglossal fossa. No mylohyoid line isevident.

    Basal aspect. Although much of the base ismissing, the preserved contours suggestthat it was everted posterolaterally. Thepreserved basal contour is rounded.

    Occlusal aspect. The postcanine tooth rowsare almost parallel and set close together.The original minimum distance between thecanine crowns before distortion can be esti-mated at about 20. Minimum distancesbetween the lingual sides of the oppositeteeth are: P3P3 253, P4P4 272, M1M1252, M2M2 254, M3M3 about 265.This last measurement is an estimatebecause of the slight distortion here.

    Teeth. Morphological descriptions of theteeth are given for the best preservedside, with any differences between sidesnoted.

    The LI1 is complete, with two transversecracks through its root that cause no signifi-cant distortion. The RI1 has alveolar boneadhered to its medial surface. It is missingthe inferior labial enamel, and some othersmall chips. It is split longitudinally, andtransverse cracks across its root areexpanded causing distortion. The left side isdescribed.

    This tooth is worn, exposing an area ofdentine across its occlusal plane that is 54MD by 25 LaL, with only a thin strip ofenamel around its margin. Only 69 of labialenamel and 65 of lingual enamel remains.The occlusal plane is mildly concave inlabial or lingual view and angled slightlydistally and lingually. The crown flares outmesially and distally from 43 wide mesio-lingually at its base to 59 at its occlusaledge, and would have been wider before itwas worn. Lingual and labial surfaces aretransversely convex. The lingual surface isconcave SI above its prominent basal bulge.Traces of mesial and distal lingual groovesare left just below the occlusal margin. Atiny area of the IPF remains at the occlusaledge of the mesial surface. Faint traces oftransverse hypoplastic lines are visible onthe labial face. The root is strongly convex

  • 266 . . ET AL.

    labially and concave lingually, measuringabout 175 in length from the labial side ofthe cervix. It swings mesially just at its apexand there is a distinct mesial groove. At thecervical margin, it measures 41 MD by 73LaL.

    The right I2 is broken in a similar way tothe right I1. It is missing the mesiolingualcorner of its crown, so the completely pre-served left I2 is described. This tooth has alongitudinal crack, but has suffered negli-gible distortion. It has dentine exposedacross the entire flattened occlusal surface(59 MD by 34 LaL) except for a narrowrim of enamel. Only 65 of enamel is left SIlabially, and 74 lingually. Both sides of thecrown flare from the cervix increasing MDfrom 48 to 66. The occlusal plane appearsto slope slightly mesially and lingually, butthis impression is mainly due to the higherdistolabial corner. Its labial face is uniformlyconvex in all directions. The lingual facepreserves shallow mesial and distal groovesand a mild median ridge above the basalswelling. Interproximal wear has marked themesial margin of the occlusal face, but nofacet is measurable. The root is 45 MDnear the cervical margin, but mandibularbone and matrix obscures its LaL dimen-sions. It is 174 long and swings distally at itsapex.

    The left /C is missing its mesiolabialcorner, and other small areas of enamel. Theright one is complete, so is described. Thiscrown is a rounded rhombus in occlusaloutline. Its occlusal wear plane runs throughthe high Mmr, and across the crownthrough the low Dmr located near thecervical margin. The wear plane is angledslightly to slope lingually but is horizontal ina mesiodistal direction, except where it turnsto slope sharply inferiorly along the distalmargin of the crown. The exposed dentineis hollowed out inside the narrow enamelrim. Although the mesial and distal basalmarginal ridges are worn at their highestpoints, they are intact and confluent as

    they swing around the base of the crownlingually. Labially, they are faint, as are thelabial grooves. The lingual ridge is asym-metrical, and has a sharp distal margin alonga narrow distal lingual fossa, but a flat mesialedge that merges gently with the distal edgeof the broad, shallow mesiolingual fossa.The labial surface is tightly convex trans-versely, and somewhat so SI. Hypoplasticlines are visible on labial and lingual faces,and perikymata are apparent on the labialface. Root dimensions cannot be measured,but on the right side the canine root isexposed for most of its length, and can beseen swinging gently distally.

    Both P3s are well preserved, but the rightone shows slightly less wear so the descrip-tion is based on this. The occlusal outlinewould be rhomboidal but for the inflateddistolingual corner. This tooth has one maincusp near the center. Dentine is exposed in a1 wide pit on the Prd, and along the distalocclusal ridge. The mesial and distal occlu-sal ridges and transverse crest are sharpand prominent. The transverse crest has acuspule representing the Med where itmeets the Mmr and Dmr. Lingually theMmr is narrow and low, arching towards thebase of the crown, and bounding a narrowFa that opens lingually close to the Med.The Dmr is stronger and higher, andbounds a larger Fp. Buccally, there is apit-like mesiobuccal groove alongside theMmr. The Mmr swings inferiorly and dis-tally to merge with the basal enamelswelling. There is only a shallow trace ofa distobuccal groove. The buccal faceslopes strongly toward the cusp apex, and isbiconvex. An IPF measuring 47 BL hasflattened the distal margin of the tooth.Three roots are present. The two distinctbuccal roots diverge apically.

    The P4s are also well preserved, butslightly more occlusal enamel remains onthe left one on which the description isbased. The occlusal outline is asymmetrical.The left P4 is rhomboidal in outline,

  • 267AUSTRALOPITHECUS ANAMENSIS

    although the right one has a less extensivemesiolingual corner and presumably asmaller Med originally. There are two cusps.The Prd is large and the Med much smaller.The Prd is almost completely worn off,exposing dentine that extends to the mesialand distal margins of the tooth, widening to21 BL at the cusp center and making itlower than the Med. A pinpoint of dentine isvisible on the Med. A pit-like remnant of theFa remains, as does a lower and largerFp surrounded by a prominent Dmr. Thelingual face is straight vertically, and mildlybilobate in occlusal profile, with two faintvertical enamel wrinkles. The labial face isbiconvex and slopes towards the buccalcusp. A faint distobuccal groove remains,indenting the occlusal profile of the crown.Interproximal wear has flattened mesial anddistal margins of the tooth. The mesial IPFis 47 LaL, and the distal one is 60 LaL.

    Both M1s are well preserved, but the leftone is missing a small piece of enamel fromits mesiobuccal corner. Description is basedon the right, even though it is missing apiece of enamel along its distal margin. Theocclusal outline is a rounded rectangle. Thebuccal side is worn more heavily than thelingual side, so that the buccal cusps, Hldand all foveas have been replaced by anelongate, hollowed area of dentine. Thelingual cusps have pinpoints of dentineexposed, and on the Med, this area ofdentine extends halfway down towards theFc. Wear has obscured details of relativecusp sizes but the Med is the highest, and islarger in area than the End. The Mmr isalmost worn through by interproximal wear.The Dmr is intact on the unbroken left side.The mesiobuccal groove is set slightly mesialto the lingual one. It continues across thevertically convex buccal face where itbecomes doubled, and forms a stronglybilobate occlusal profile as it continues tothe cervix. The lingual groove is more pro-nounced occlusally, and is sharp as it cutsthe occlusal margin and passes along the

    vertical, bilobate lingual face to the cervicalline. Interproximal wear has left a broadconcavity in the mesial occlusal profile,and has flattened the distal profile of theunbroken left side. On the right, the mesialIPF measures 61.

    Although both M2s are completely pre-served, the right one is described because itis slightly less worn. This tooth is a roundedrectangle with bilobate sides with a barelyconcave mesial margin caused by inter-proximal wear. The buccal cusps are muchlarger than the lingual ones, and togetherwith the Hld comprise more than half thecrown. The lingual ones are higher as pre-served, with the Med the tallest. The entiresurface is worn, but dentine is exposed in a17 MD slit on the right Prd. The slit-like Fais located to the lingual side of the MD axis,as are the Fc and Fp. Only a trace of the Fpremains. The lingual and mesiobuccalgrooves are continuous across the crown.The lingual groove sharply incises theocclusal margin, and continues to the cervix.Faint vertical enamel wrinkles mark thevertical lingual face. The mesiobuccalgroove splits just before it passes the occlusalmargin, and has a mesial branch that termi-nates occlusally at a large protostylid, and adistal branch that continues to the cervixalong the distal margin of the protostylid.Immediately posterior to this branch arethree small, vertical enamel grooves extend-ing along the superior half of the slopingbuccal crown face. The distobuccal grooveis largely obliterated by occlusal wear, and isfaint along the side of the crown. The mesialIPF indents the mesial occlusal profile andmeasures about 50 BL. A distal IPF isobscure, although one is visible on the leftM2.

    The M3s are both missing pieces ofenamel from their distobuccal corners, butthe right one is missing more. The left onehas a crack through the mesial cusps and thetip of its Med damaged. Description isbased on the left. This tooth is an elongate

  • 268 . . ET AL.

    Figure 2. Holotype temporal, KNM-KP 29281B in lateral and inferior views.

    rectangle in occlusal outline. The occlusalsurface is worn with polishing on all cuspsand flattening of the buccal cusps and Hld,but no dentine is exposed. The Med ishigher than the others, but the Prd is largestin area. There is a large Hyd and a smallerEnd. Each is divided into mesial and distalparts by grooves. A C6 is present and largerthan the Hld. A deep, transversely wide Faruns from the MD axis of the crown to thelingual margin, bounded by the Mmrmesially and a transverse ridge connectingthe mesial cusps distally. There is no Fp.The lingual and mesiobuccal grooves aredeep and continuous, meandering across thecrown, incising the occlusal marginsstrongly and continuing to the cervicalmargins. Vertical enamel grooves are visibleon the buccal, lingual and distal faces, someof which incise the occlusal margin. Noprotostylid is visible on the left M3, althougha distinct one is seen on the right one. TheM3 roots incline strongly buccally andmildly distally, as seen on the damaged rightside.

    B: Left temporal fragmentThis pieceof left temporal bone consists of a maximum

    of about 52 AP. About 25 SI of thesquamous portion remains, as does much ofthe temporomandibular joint and thetympanic with the external acoustic porus.Laterally, the zygomatic process is brokenoff at its base from the prearticular areaposteriorly, cutting through the mandibularfossa and postglenoid process. Several largeair cells are exposed here. The lateral marginof the external acoustic porus is preserved atits inferior edge, but the rest of the margin isbroken away. The inferior surface of thefragment extends posteriorly from the sphe-nosquamosal suture. It preserves much ofthe articular surface, part of the prearticulararea and inferior surface of the tympanic.The sphenotemporal suture is preservedabout 25 anteriorly from the tympanic. Themedial surface of the fragment shows amixture of broken bone pieces and matrix.

    The small remaining piece of the squamehas fine ridges running superoposteriorly,especially on its posterior part, that followthe course of the temporalis musclefibers. There is a small tubercle about 45anterior to the most anterior portion of thezygomatic root, in the position to have been

  • 269AUSTRALOPITHECUS ANAMENSIS

    associated with a septum that divided thetemporalis muscle. It lies at the anterior endof a faint linear ridge that, like the striationsfurther posteriorly, runs superoposteriorlyacross the squame. The external auditoryporus is small and elliptical in outline. Itslong axis is oriented 90 to the superiorsurface of the zygomatic origin. The porusmeasures a maximum of 89 by 57 aspreserved.

    The articular tubercle is flat, with only amild convexity demarcating it from the in-ferior temporal surface. The tympanic platemakes a large angle with the articular surfaceof the temporomandibular joint, so that thewhole of this medial part of the temporo-mandibular joint is just one shallow, cup-like cavity. It is not possible to estimate howmuch of the articular surface extendedlaterally past the squame, but about 20 ispreserved medially. The squamotympanicfissure is represented by a 64 long slit in themiddle of the cavity. The postglenoid pro-cess is fused to the tympanic, and wouldhave continued laterally to it. As preserved,the tympanic plate measures 116 AP fromthe squamotympanic fissure to the brokenedge of the stylomastoid foramen and 263perpendicular to this to the edge of theacoustic porus. The sheath of the styloidprocess is partly preserved on the posterioraspect of the tympanic.

    On the medial surface, some remainingpieces of bone appear to be endocranialbone and one has a trace of a meningealvessel groove on it, but on the whole thisfractured surface is uninformative.

    KNM-KP 29282: LM1 or M2 (not figured).This is a broken molar, either M1 or M2,preserving a worn crown and partial roots. Itwas discovered during screening, just wash-ing into the sandy stream channel at the baseof the slope from which the type specimen,KNM-KP 29281, and the worn premolarand molar, KNM-KP 31730 were found(Wynn, 2000, Figure 2). It is possible that

    this specimen is the same individual asKNM-KP 31730, but separate accessionnumbers have been allocated because of thelarge distance, from the base to the top ofthe slope (approximtely 10 m), separatingthe two specimens.

    The molar is the most heavily wornmandibular molar in the sample, withdentine exposed over the entire occlusalsurface. The roots are nearly completebuccally, but are largely missing lingually.Mandibular bone is preserved between theroots, but only the buccal cortex remains.The occlusal outline is rectangular. Thebuccal side is broken, and enamel is missingfrom the mesiobuccal corner, and distal sideof the crown. The smaller area of lingualdentine is set at higher plane than the muchlarger buccal portion, which is stronglyhollowed out transversely. On the buccalface, the mild mesiobuccal groove extendsto the cervical margin. Wear and damageobscures any potential evidence of a proto-stylid. A tiny portion of the mesial IPF isvisible and contacts the occlusal margin.Distally no IPF is preserved. The remainingmesiobuccal root is at least 145 long andless distally inclined than is the remaining115 long distobuccal one.

    KNM-KP 29283: Maxilla (Figure 3). Thismaxilla was a surface discovery, but the I1

    and both lateral incisors were recoveredseparately through excavation.

    Preservation. This is a weathered adultmaxilla with all teeth except the left I1 andright M3. The maxilla is preserved in twohalves. Both preserve the intermaxillarysuture anterior to the nasal aperture.Posterior to this, the left side preserves thesuture inferiorly along the palatine process.The right side, however, is broken 3 laterallyfrom the midline on the palatine process.Therefore, the two halves can be articulatedonly anterior to the incisive foramen andnasal aperture. The superior portion of theclivus is missing on both sides of the midline

  • 270 . . ET AL.

    Figure 3. KNM-KP 29283 maxilla with associated I2s. LI2 in lingual, distal and mesial views; RI2, inlingual, distal and mesial views; maxilla in facial view at top, second row, superior and palatal views; thirdrow, left and right lateral views; bottom row, left and right medial views.

  • 271AUSTRALOPITHECUS ANAMENSIS

    within the nasal aperture. The incisor alveoliare partially preserved, with their labialportions broken away. The labial and buccalmargins of the canine alveoli are brokenaway over the entire length of the canineroot on the right, and for much of it on theleft. On the right side, the P3 buccal rootsare exposed and much of the P4 roots, but itis impossible to tell how much of the rootexposure is due to damage and not resorp-tion. The right I1, both I2s and the RC/ werefossilized separately. On the left side, themaxillary tuberosity is eroded, exposingcancellous bone. Only about 10 of bone ispreserved above the alveolar margins. Thereis lateral exposure of the distal M1 root,probably due to abrasion.

    Facial aspect. The anterior margin of themaxilla is slightly convex transversely wherepreserved. There is a mild, vertical depres-sion laterally where the bone flares aroundthe canine jugum on each side. The I2

    alveoli are set lateral to the nasal cavity. Theinflated canine juga and the anterior P3 jugaform large rounded anterolateral corners tothe profile of the bone. The nasal aperture issmoothly continuous with the external sur-face of the bone. No ridges or crests delimitthe preserved portion laterally or inferiorly.The lateral walls of the aperture extend 125superior to the floor on the right and abouthalf that on the left. The nasal aperture is223 wide. A depression about 8 wide justinside the lower lateral margin of the nasalaperture is delimited posteriorly by arounded ridge that runs posteriorly andsuperiorly from the posterior edge of theclivus.

    Lateral aspect. The lateral contour of thealveolar process is gently convex. Thecanine fossae are asymmetrical and quiteirregular. On the right side, the canine fossais deep and measures just over 1111.There may be some pathology, also sug-gested by an irregular and convoluted floorof the maxillary sinus on this side comparedwith that of the left. On the right side, the

    alveolar bone along P3 to M1 is resorbed,exposing the bases of the roots. Just postero-inferior to the canine fossa, right above thetips of the distobuccal P3 and single buccalP4 roots, there is a circular depressionmeasuring 5 in diameter of obscure origin.The root of the zygomatic is preserved as araised area of abraded bone. Inferior to it isa shallow depression, bounded posteriorlyby the rounded jugum for the distobuccalM1 root. The jugum for the distobuccal rootof M2 is pronounced. These juga give thelateral margin of the alveolar process amildly undulating profile. Similar contoursare seen on the more abraded left side. Onthe left, however, the canine fossa appears tohave been smaller, although it is brokensuperiorly. There is also less root exposure.

    Inferior aspect. The postcanine tooth rowsare almost parallel to each other, and areslightly concave lingually. Minimumbreadths of the palate between teeth are: C/34, P3 38, P4 385, M1 38, and M2 355.The palatine processes rise graduallyposteriorly, so that the palatal depthincreases steadily. As measured from toothcervices, palatal depth is 6 at P3, 8 at P4,105 at M1, and 125 at M2. The length ofthe tooth row from the mesial side of C/ todistal M3 is 633. The incisive foramen isabout 5 in transverse diameter and is cen-tered 17 from the alveolar margin, betweenthe P3s. The greater palatine foramen is notpresent, but the vascular groove is, lying atthe inflection between the alveolar and pala-tine processes. On the left side, a severealveolar resorption pit measuring 15 AP hasexposed up to 90 of the M1 roots and 40 ofthe P4 root. On the right side, resorption isless extreme, but is present in roughly thesame location.

    Superior aspect. The nasal cavity is narrow-est at a point just posterior to the internalridge, where it is about 215 wide, broaden-ing posteriorly to about 27 above the level ofthe M1. On the left, the maxillary sinus as itis exposed is 46 AP, running from a point

  • 272 . . ET AL.

    level with P4 to the posterior break. It is upto 15 ML, with its widest point above M1. Itis divided into a large anterior cavity, a smallmiddle cavity superior to M3, and an evensmaller one posterior to that. There is a faintdivision of the larger cavity separating theroots of M1 and M2. The right maxillarysinus reveals a more complex set of irregularloculi than the left, with a deep anterolateralpocket reaching down towards the caninefossa, and two smaller pockets preservedsuperior to the canine root. The sinus ispreserved for 37 AP, running from the levelof P3 only to M2. It is up to 17 ML at the M1

    level.Medial aspect. Subnasal anatomy is

    exposed on the midline break. The incisivecanal is 32 wide in the sagittal plane nearthe foramen and expands posteriorly toabout 6 near the nasal cavity. The long axisof the canal runs superiorly and posteriorlyat an angle of about 25 to the inferiorsurface of the palatine process. The naso-alveolar clivus is a maximum of 114 thick.From the anterior margin of the nasalaperture, the floor of the nasal aperturepasses backwards about 13 before droppinginferiorly about 12 to the palatine processes.The left palatine process, which preservesthe midline suture, expands in thicknessposteriorly from a thin apex at the incisivecanal to 6 at the level of M2 at midline. Theopening of the incisive canal is just over 12across, and it opens posteriorly and laterallyto the widest portion of the nasal cavity.

    Teeth. The teeth are heavily worn,especially anteriorly. The right ones are lessheavily worn, so these are described whereboth sides are preserved. Little detailedocclusal morphology remains. There is aclear heliocoidal wear pattern along eachtooth row.

    The right I2 consists of the root and thelabial portion of the crown. The labialenamel is only preserved for an arc 32mesially and 22 distally. The lingual side isworn well below the original cervical

    margin, so that the occlusal plane wasoriented superolingually and slightly dis-tally. The root is broken superiorly, but canbe replaced into the preserved portion of itsalveolus. The root is 22 long. It is triangularin outline near the cervix and becomesrounder apically. The root is convex in out-line on its labial side and concave on thealveolar side. A mesial groove is present.

    The I2s are morphologically similar, sothe more complete left one is described.Only 24 of enamel remains labially on theleft, although 38 remains on the right. Theroot is worn down below the original cervi-cal margin lingually, so that the occlusalwear surface is strongly angled labially. It isalso angled to slope lingually and distally. Anarrow band of enamel remains mesially,but almost none distally. The root is 22 longfrom the labial enamel line. It is stronglycompressed MD, measuring 46 MD by82 LaL near the cervix, and is hookedlabially at its tip. The preserved labialand lingual margins of the root are mildlyconvex, so that it widens to a maximum of90 LaL. The root has mild mesial and distalgrooves.

    The canine has only 35 of the labialenamel and a thin ribbon of distal enamelremaining. Its occlusal surface is planar andslopes lingually. Almost the entire root isexposed. It is fairly straight but convexlabially, 286 long. It is oval in section,measuring 90 MD by 115 LaL near thecervix. The root has a mesial groove. It isnearly vertical, with its long axis orientedat over 85 to the cervical margins of thepostcanine teeth in lateral view.

    All that remains on the P3 crown is a verythin rim of enamel. It had about 6 of buccalenamel remaining, but most of the buccalenamel has been broken away. The dentineexposure is hollowed out. Mesial and buccallabial grooves extend about 2 superiorlyfrom the occlusal plane, and there is apronounced basal enamel bulge. It has threedistinct roots. On the right, the roots are

  • 273AUSTRALOPITHECUS ANAMENSIS

    exposed for 130 mesially and 127 distally,which is most of their length. The mesio-buccal and distobuccal roots diverge atabout 30.

    The right P4 is displaced superiorly. It hasenamel chips missing from its buccal andlingual surfaces. The left P4 has lost enamelfrom the mesiolingual corner. Some occlusalenamel remains between the cusps and inthe Fp. A 32 wide area of dentine isexposed lingually, but the buccal exposurecannot be measured owing to damage.Extensive contact facets are evident, alteringthe mesial and distal faces of the crown.

    The left M1 is missing enamel on most ofthe mesial half of the tooth, and the rightone is missing a small piece from the disto-lingual corner. In occlusal outline the M1

    tapers distally. The lingual half of the crownis a heavily excavated dentine basin sur-rounded by a 2 high thin rim of enamel.Wear has flattened the buccal cusps.Dentine exposure is difficult to assess due toweathering, but there is a clear 13 widedentine pit on the Pa. The two buccal cuspsare mostly preserved, with the Me the larger.A pit-like Fp remains bounded by a Dmr.The buccal groove is pronounced, and con-tinues to the cervical margins making thebuccal face strongly bilobate. Interproximalwear has removed much of the mesialenamel.

    The occlusal outline of the M2 also tapersdistally. The preserved buccal cusps areroughly the same size and flattened bywear. Dentine is exposed as a continuousexcavated strip along the two lingual cusps.There is also a 1 wide dentine pit on the Pa.The shallow remains of a Fp are present.Both lingual and buccal faces are bilobate,with lingual and buccal grooves extending tothe cervical margin. A weathered distal IPFis visible but cannot be measured.

    The M3 has a strongly tapered occlusalprofile, with a rounded distal margin. Themesial cusps are substantially larger thanthe distal ones, occupying most of the

    crown. The Pa is higher than the distalcusps. The occlusal surface is flattened bywear and there are two mesial dentineexposures, 19 BL on the Pa and nearly 5and deeply excavated on the Pr. The lingualand buccal grooves are mild, and extend allthe way up the crown faces.

    KNM-KP 29284: R/C and RP3 germs(Figure 4). This specimen was found in situin an excavation to recover further partsof the adult maxilla, KNM-KP 29283.Because these two teeth are germs they areclearly from a different individual.

    A: R/C. This is the nearly completecrown or a /C germ that is slightly weatheredand cracked around its cervical half. Thereis no trace of any root formation. It isstrongly asymmetrical. In occlusal outline, itis almost a quadrilateral with corners mesio-labially, mesiolingually, distolabially andthe most prominent one distolingually. Itslingual face is marked by pronounced mesialand distal lingual fossae and a sharp lingualridge, all of which are concave distally. Themesial edge of the lingual ridge is rounded,but its distal edge is sharp. The high Mmris faint as it passes the mesial edge. Theincisive and cervical halves of the sharpmesial margin are set at about 30 to oneanother in lingual view. The cervical portionalmost parallels the distal margin of thecrown and the incisive portion angles dis-tally towards the apex. The sharp distalmargin of the crown is concave, swingingout inferiorly to meet a strong distal basaltubercle 100 from the crown tip and 33from the preserved base. This tubercle existsas the pinnacle of the Dmr, which inclinesinferiorly both lingually and labially, butmore steeply labially. Lingually, it meets thebase of the lingual ridge. Nested just abovethe distal tubercle there is a smaller tubercle.Labially, there is a broad distolabial groovewith a sharp distal edge and a gentler mesialedge that blends into the labial face. Thelabial face is tightly convex transversely, but

  • 274 . . ET AL.

    Figure 4. Dental specimens from Kanapoi not associated with jaw fragments. KNM-KP 29284A inlingual, distal and occlusal views, KNM-KP 29284B in lingual and occlusal views, KNM-KP 30505 inocclusal view, KNM-KP 30502D, KNM-KP 30502E, KNM-KP 31714, KNM-KP 31723 in occlusalview, KNM-KP 31717A in mesial, distal and occlusal views, KNM-KP 31717B and KNM-KP 31726 inocclusal view, KNM-KP 31729 in buccal, distal and occlusal views, KNM-KP 31728, KNM-KP 35842,KNM-KP 31730A and KNM-KP 31730B in occlusal view, KNM-KP 35847 in buccal and occlusal view,and KNM-KP 35852 in mesial and occlusal views.

  • 275AUSTRALOPITHECUS ANAMENSIS

    is almost straight SI. There is almost nomesiolabial groove, only a sharp, straightedge inferior to the Mmr. Hypoplastic linesare evident on the lower half of the labialface, with a particularly strong one 24above the inferior margin. Perikymata arealso visible.

    B: RP3. The crown of this germ is almostcomplete with no trace of root development.It is split in two by a vertical crack passingmesiodistally through its middle, but it is notdistorted. Lingual enamel is broken awayfrom the sides adjacent to the basins,although more extensively so around the Fp.Enamel is also missing from the inferioredge of the distal margin of the crown. Thecrown has an ovoid occlusal margin, withthe long axis running mesiobuccally todistolingually. The large Prd is located in thecenter of the tooth. The mesial and buccalocclusal ridges and transverse crest aresharp. The transverse crest meets a tinyMed. The mesial ridge is continuous withthe sharp Mmr. The distal ridge meets theDmr at a distal tubercle. The Fa is BLnarrow, and the Fp is broader with its sidesmarked by radial wrinkles. The buccal sur-face of the tooth is convex transversely. It ismildly convex SI, inclining strongly towardthe Prd. Mesial and distal labial grooves arebounded by sharp marginal ridges. Faintvertical enamel ridges are visible on thebuccal face.

    KNM-KP 29286: Mandible fragmentswith associated mandibular dentition(I1, L & R I2M3) (Figure 5). Apart fromthe fragments that make up KNM-KP29286A, this specimen was recoveredthrough screening and comprises a completeset of lightly worn associated teeth. Severalhave their roots embedded in expanded andcracked mandibular bone and matrix. Sev-eral tooth fragments that do not appear tobelong to this specimen were also recoveredbut given a separate accession number,KNM-KP 31732.

    A: R mandibular fragments (I2P3).This piece of mandible is badly broken. Theonly remaining cortex is about 1 along itsinferior edge below I2 and much of the areabelow P3, although here it is weathered. Thealveolar margin between I2 and /C is mildlyabraded but close to preserving its originalcontour. Most of the rest of the bone isbadly splintered, distorted and intermingledwith matrix. The mesial wall of the P4alveolus is exposed at the posterior break.

    The tip of the I2 crown is broken off, withenamel preserved only 39 labially and 57lingually. The break exposes the pulp cavity.The root is complete although the tip isseparated from the rest of the tooth by a 3wide transverse crack. The superior halfis displaced slightly labially relative to theapical end, which appears to be in itsoriginal position. Most of the tip is obscuredby matrix. The I2 lingual face preserves amild basal tubercle, above which it is gentlyconcave SI and flat transversely. The gentlyconvex labial face has faint vertical enamelwrinkles and perikymata visible. The rootmeasures 51 MD by 80 LaL near thecervical margin. The exposed side of theroot has a mesial groove.

    The canine crown is complete except for asmall area of enamel at its distolabial cervi-cal margin. The distal half of its root iscomplete, but the mesial half is missingabout 11 from the mesial cervical margin,exposing the pulp cavity throughout itslength. The canine crown measures 143high labially as preserved, and was probablyabout 15 before wear. It is highly asym-metrical. The tip of the cusp is worn trans-versely, preserving a tiny spot of dentine,and polishing extends most of the way alongthe distal crown margin. The mesial marginis sharp, making a 30 bend at the Mmr inlingual view at midcrown. The Mmr swingsdistally and cervically, terminating inferiorto the wide and deep mesiolingual fossa. Inlingual view, the distal margin of the crownbecomes concave towards the distal basal

  • 276 . . ET AL.

    Figure 5. KNM-KP 29286 associated mandible fragments and mandibular dentition. On left, (A), (B),(C), (D), (G), (H), and (I) in occlusal view; (J) in lingual view; (E) in two pieces, mandible fragment withI2 in labial view, and LC in mesial view; bottom right, (A) in lateral view.

    tubercle. The Dmr is faint, extending fromthis tubercle mesially. The lingual ridge issharp at its top, but widens inferiorly. Thedistal lingual fossa is a narrow slit. The labialface is transversely convex and mildly so SI.There is almost no mesial labial groove, buta wide, shallow distal labial groove. There islittle basal swelling of the crown on any side.Hypoplastic lines mark the labial surface.The root measures 80 MD by 117 BL nearthe cervical line. It has a pronounced mesialgroove. The canine alveolus measures about30 deep. The pulp cavity is about 55 wideLaL.

    The P3 crown is complete, with somehairline cracks through it that cause nodistortion. Most of the middle portion of itsmesiobuccal root is missing. This lightlyworn P3 has a large Prd occupying thecenter of the tooth. The mesial and distalocclusal ridges and transverse crest aresharp, as are the marginal ridges. All showsome polishing from occlusal wear. There isan incipient Med. The Fa opens lingually,because the Mmr dips almost to the cervicalline. The Fp is larger and opens superiorly,as the Dmr is more pronounced and higherthan the Mmr. Buccally, the Mmr and Dmr

  • 277AUSTRALOPITHECUS ANAMENSIS

    merge with a horizontal basal enamel swell-ing. Above it, the strongly sloping buccalface is convex transversely and straight SI.The labial grooves are moderate.

    B: RP4. This is the crown with up to 43of the root. Cracks run through the crownbut cause no distortion. The occlusal outlineis a broad oval that is slightly broaderlingually. It is lightly worn. This tooth isbicuspid. A large Prd occupies about halfthe crown, its apex about one third of theway from the buccal margin in occlusalview. The Med is smaller but almost as high.Mesial and distal occlusal ridges arerounded. The transverse crest is notched inmesial or distal view. The shallow Fa issmaller and higher than the Fp, but both aremarked with enamel wrinkles. The Mmr isnarrow and meets the base of the Med. Thestronger Dmr meets the Med nearer its apexand close to a pit that is separate from theFp. The buccal face is convex transversely.It is nearly straight vertically, slopingstrongly towards the apex, with a gentlebasal swelling that connects the mesial anddistal labial grooves. The distal labial grooveis more pronounced than the mesial one,and delineates a small cuspule at theocclusal margin. An obliquely set mesialIPF measures 28 BL by 14 SI. Anotheroblique, lingually placed distal IPFmeasures 41 by 21. The preserved top ofthe root has grooves mesially, mesiolinguallyand distally.

    C: RM1. This crown is complete andpreserves up to 2 of the root. The crown isalmost square but slightly elongate MD.From largest to smallest the cusp areas are:Prd, Med, Hyd, End, Hld. All show wear;the lingual cusps are facetted and the buccalflattened with small areas of dentineexposed. A protostylid is present, delineatedfrom the Prd by a narrow slit along itsmesiobuccal corner. The Fa exists as a slitrunning up the Med nearly to its apex fromthe Mlg. Distal to it is a less extensivegroove, bounded posteriorly by a ridge

    connecting the two mesial cusps. The Fp is acleft connecting the End and Hld. It istraversed by the distal lingual groove, whichdisappears about halfway down the disto-lingual crown face. The sharp lingualgroove deeply incises the occlusal marginbut disappears halfway down the verticallingual face. The mesiobuccal groove is deepnear the occlusal margin, but is only a broadand shallow depression towards the cervix.The buccal face is strongly bilobate, and thelingual face is straighter. The distobuccalgroove terminates near the occlusal margin.A mesial IPF measures 47 BL by 23 SI anddoes not meet the occlusal plane. A faintdistal IPF measures about 3 BL by 2 SI.

    D: R mandibular fragment (M23).This is a piece of badly splintered mandibu-lar bone that preserves no morphology. Thecomplete M2 and M3 crowns are present,with roots partially encased in extensivelycracked bone.

    The M2 tapers distally with a roundeddistal margin. From largest to smallest, thecusp areas are: Prd, Med, End, Hyd andHld. The tooth is lightly worn; the lingualcusps are facetted and the buccal flattenedbut without dentine exposure. Its foveasresemble those of the M1. The mesiobuccalgroove passes the protostylid to fade outtoward the cervical margin. The lingualgroove incises the occlusal margin stronglybut is faint on the lingual face. The disto-buccal groove is shallow on the side of thecrown and disappears just past the occlusalmargin. The protostylid is found only on thebuccal face of the Prd and is most pro-nounced at the mesiobuccal groove. Thebuccal and lingual faces are like those of M1.Vertical enamel wrinkles mark the buccalface. The mesial IPF is weathered andcannot be reliably measured. The distal IPFis a sliver 32 BL along the occlusal margin.

    The M3 is lightly worn on all cusps. It ismesiodistally elongate with a receding,rounded distobuccal corner. Relative cuspsizes and shapes are the same as for M2,

  • 278 . . ET AL.

    except that the Hld is smaller and there is asmall C6 adjacent to its pit-like distal fovea.The occlusal surface enamel is crenulated.The Fa is a broad single slit markedby vertical enamel wrinkles. The deepmesiobuccal groove continues to a pointnear the cervix, just distal to a distinctprotostylid that flanks the entire buccal faceof the Prd. The lingual and distobuccalgrooves both disappear midcrown. Themesial and buccal sides resemble those ofthe other molars. Faint vertical enamelwrinkles mark all sides of the crown.

    E: L mandibular fragment (I2/C).This fragment of mandible is badly splin-tered. Part of the distal wall of the I2 alveolusand mesial wall of the /C alveolus remain.The I2 has its crown broken diagonally sothat the exposed face is angled distally. Thepulp cavity is exposed. Up to 74 of enamelis preserved lingually and 65 labially alongthe mesial edge. A chip of enamel is missingat the mesiolabial corner. A 1 wide trans-verse crack divides the root just below thecrown lingually and 44 below it labially.The apical end of the root is missing pastabout 7 from the crown. The /C is missingthe distobuccal corner and superior half ofits crown. The root is preserved for up to133 of its length. The morphology of theseteeth is like those of the right side.

    F: L mandibular fragment (P3, rootsP4). Small amounts of cortex remain on thisfragment, but no morphology is preserved.The P3 is complete. Two broken roots of P4are visible. The P3 is like the right one, but ismore compressed MD, with a slightly lowercrown and lower Dmr.

    G: LP4. This is the crown with up to 45of its root. It cannot be joined to fragment Fdescribed above. The crown is split by a thinmesiodistal crack, but has suffered negligibledistortion. An obliquely set mesial IPFmeasures about 2 BL by 1 SI. A moredistinct, oblique, lingually placed distal IPFmeasures 29 by 18. In all other aspects itresembles the RP4.

    H: L mandibular fragment (M1). Thisis the crown and partial roots of the toothencased in badly splintered mandibularbone that preserves no morphology. A smallpiece of the lateral surface of the body about9 long is visible, but not in its originalposition. The M1 crown is nearly the mirrorimage of the right one, except that a distincttransverse pit is located along the disto-buccal groove incising the edges of the Hydand Hld. The protostylid is more extensiveextending almost to the mesiobuccal groove.Vertical enamel wrinkles are visible on thebuccal and lingual faces.

    I: L mandibular fragment (M23).These complete M2 and M3 crowns havepart of their roots preserved, encased in abadly fragmented piece of mandibular bone.The only original bone that remains inposition is the alveolar margin around M2.Details of the occlusal groove pattern differbetween sides, and the left ones are lessworn, but these teeth are essentially mirrorimages of the right ones. The M3 has a largerHld and a double C6, contributing to itsmore rectangular occlusal outline comparedto the right.

    J: I1. This is most of the crown weatheredin patches. The long IPF on one sidesuggests that it may be a right, as listedin Leakey et al. (1995), but because theother side of the crown is too weathered toassess, this tooth cannot be attributed to aside with certainty. The top of the root isvisible mesially and distally, but the crowndoes not reach the cervical line labiallyor lingually. The tooth is worn, exposing astrip of dentine. The lingual side has gentle,broad mesial and distal lingual fossae. Thelabial side is straight and flat. The IPFmeasures 52 SI by 16 LaL, and occupiesmost of the right side of the crown in lingualview.

    KNM-KP 29287: Mandible with teeth(Figure 6). This specimen was largelyrecovered through screening. The initial

  • 279AUSTRALOPITHECUS ANAMENSIS

    Figure 6. KNM-KP 29287. Top row left, occlusal view of mandible KNM-KP 29287 A and B, and right,incisors KNM-KP 29287 C, H, D from right to left in lingual view, and below KNM-KP 29287 C inmedial view. Middle row, mandible KNM-KP 29287 A and B in left lateral views. Bottom row, mandiblein right and left medial views.

    discovery, two fragments of left and rightedentulous mandible, were found close tothe to the origin of a small stream channel.Subsequent screening for about 50 m along

    this channel led to the recovery of numerousbone and tooth fragments that were recon-structed to make up this almost completemandibular body.

  • 280 . . ET AL.

    A: L mandible (alveoli I2/C, partialcrowns P4M2, roots P3, partial rootsM3). Preservation. This is a mandible of anadult. The left body is more poorlypreserved than the right, so mandibularmorphology is described for the right side(B). The left portion of the mandible ispreserved anteriorly from a point just lateralto the symphysis internally and about 14anterior to the mental foramen externally,and extends to the third molar distal rootsposteriorly. The left body is damagedanteriorly, with a break passing transverselythrough the alveolus of the I2 and /C. Thebase is missing, with cortex preserved for amaximum of 28 inferiorly from the alveolarmargin on the lingual face. The alveolarmargin is intact only along the lingual side ofM2, and it is abraded everywhere else. Thepreserved cortex is cracked throughout andweathered in places, but distortion appearsminimal. A carnivore tooth mark is visibleanterosuperior to the mental foramen.

    Morphology. The mandibular canal isexposed along the broken inferior surfacefrom the posterior break to a point inferiorto the M1M2 junction, and is about 56 indiameter. At the posterior break, thereappears to be a crypt situated just lingual tothe mandibular canal for a supernumerarymolar or a Stafnes or other type of develop-mental cyst. The canal is at least 76 indiameter and immediately lateral to the dis-tal root of M3, which itself is seen inlongitudinal section at the posterior break.

    The single mental foramen is oval insection. Its posteroinferior margin isabraded, but it appears to have openedslightly superiorly.

    The I2 alveolus is vertically oriented, witha MD width of about 5 and an estimatedminimum depth for the I2 root of 146. Theextremely large left canine alveolusmeasures about 105 in maximum diametertransversely, in an axis running diagonallyfrom the middle of the I2 alveolus to justbuccal to the P3 root. Although a small

    triangle of bone is missing from its lateralmargin, the alveolus is apparently not dis-torted, because a CT image of the preservedright canine root and alveolus reveals com-parable dimensions (F. R. Spoor, personalcommunication). The LP3 has no crown. Asingle mesial root is visible running behindthe canine alveolus. A separate distal, plate-like root appears in the broken cross-sectionof the alveolar margin, but this root bifur-cates deeper in the mandible, as suggestedon the right side and visible on a CT image(F. R. Spoor, personal communication).

    The LP4 is almost complete, missingenamel only along its distolingual corner. Itsocclusal outline is a rounded rhombus. ThePrd is the larger of the two cusps and is setdirectly buccal to the Med. The only appar-ent occlusal wear is a flattened light facet onthe Prd that has exposed a small, circulararea of dentine about 04 across. The facet-ting runs from the tip of the Prd slightly ontothe transverse crest, and more so mesiallyonto the Mmr although it does not contactthe mesial IPF. The Med and all ridges andcrests are polished. The Fa is smaller andsituated higher than the Fp. The transversecrest is split, so that there is a small Fcbetween them. The Dmr is stronger andwider than is the mesial Mmr, and it mergesbuccally with the buccal marginal ridge. Theoval mesial IPF is 33 BL by 2 high. Itcontributes to the flat occlusal outline of themesial side of the crown. There is a singleslight lingual groove, distal to the lingualcusp. On the buccal face, there is a distinctdistobuccal groove but only a trace of amesiobuccal groove.

    The LM1 is missing enamel along itsentire mesial margin to the center of the twomesial cusps, so the Mmr and Fa cannot beseen. The crown is a rounded rectangle inocclusal outline with mildly bilobate sides.The tooth has two relatively high facettedlingual cusps, two worn and flattened rela-tively low buccal ones, a flattened Hld and asmall polished C6. The Med is the dominant

  • 281AUSTRALOPITHECUS ANAMENSIS

    cusp but the relative cusp areas cannotbe determined due to the missing mesialportion of the tooth. The buccal cusps areset mesial to the lingual ones. Wear facetsare seen on all cusps, with wear striae run-ning predominantly BL. Small, circularareas of dentine are exposed on the twobuccal cusps, with the Prd exposure biggerthan that on the Hyd, measuring about05 in diameter. The strong lingual groovetraverses the tooth surface to continue as themesiobuccal groove, but it becomes faintacross an isthmus joining the two buccalcusps. There are cingular remnants extend-ing from the mesiobuccal groove, andanother extending mesially from the disto-buccal groove. The buccal and lingualenamel lines are fairly straight wherepreserved.

    The LM2 crown is broken through themesial cusp tips and is missing its mesialportion. Its morphology is similar to thatdescribed for the right M2. A small, singledistal IPF is visible.

    B: R mandible (alveoli I2, brokenroots I1, /CP3, partial crowns P4M2).Preservation. The right body is nearly com-plete from the symphysis to the mesial partof the M3 alveolus. It has many weatheringcracks and fragments of bone missing. Thealveolar margin is complete only on thelingual side of M2 and between M1 and M2.A large SI crack runs through the caninealveolus across the entire bone, separatinganterior and posterior portions that havebeen joined together. Cracking and abrasionalong the margins of the two pieces disruptthe contours of the bone, especiallymedially, but this region does not otherwiseappear distorted.

    Lateral aspect. What is preserved of theextramolar sulcus opens anteroinferiorlyadjacent to M2. A strong lateral torus marksthe root of the ramus, and is located abouthalfway down the body from the alveolarmargin. There is a faint concavity just belowthe torus. The oblique line is obscured by

    damage to the cortex, but on the left side canbe seen to be short, extending anteriorly towhere it terminates just below the mesialedge of M1. There appears to be a slighthollowing of the bone posterosuperior to themental foramen. The single mental foramenis large with abraded margins, but probablywould have been about 4 in diameter. Thedirection it opened cannot be determined. Itis situated beneath the distal root of P3 justbelow the SI midpoint of the corpus. Antero-superior to this, the contours of the bone flareout slightly toward what would have been afairly prominent canine jugum, although thebone overlying the canine root is largely miss-ing. Only a weak marginal torus is apparentwhere the base is broken posteriorly. Thecorpus does not appear to deepen posteriorly,although much of the inferior margin is lost.At the symphyseal midline the height is esti-mated at 43, posterior to I2 it is 42, /C 44, P343, and P4 423.

    Posterior aspect. The postincisive planum ishollowed ML and almost straight AP, untilit curves into the superior torus at about thelevel of the P3 roots. The superior torus isstrong and high, located almost halfwaytoward the base from the alveolar rim. It isseparated from the strong inferior torus by ashallow and rounded genioglossal pit. Theinferior torus is as posteriorly extensive asthe superior one. The area of the sublingualfossa is obscured by a large crack.

    Medial aspect. The symphysis is long andlow, sloping posteriorly with its long axisrunning 135 to the alveolar margin. Itsexternal contour is uniformly convex, arch-ing smoothly around its inferior margin. Themylohyoid line is partly obscured by cracksand spalling, but appears as a rounded ridgerunning anteroinferiorly from the posteriorbreak. The alveolar prominence is fairly flatinferior to P4, gently curving into a shallow,anterior subalveolar fossa that appears torun parallel to the base.

    Basal aspect. At the short section of thebasal contour below the mandibular tori is a

  • 282 . . ET AL.

    pronounced concavity leading to a strongdigastric tubercle situated about 5 from themidline. Because bone is missing here, anycrest along the mandibular base is obscured.The mandibular body is noticeably evertedbetween M2 and M3. The small preservedportion of the mandibular base is smooth,forming a rounded ridge along its inferior-most extent. There is a small, longitudinalridge that begins near the anterior-mostpreserved portion of the base.

    Occlusal aspect. Corpus thickness can beestimated at P3 (22), at P4 (20), at M1 (21),and at M2 (23), but these estimates arerough due to spalling and weathering.

    Teeth. On the right no canine crownremains, but pieces of the right canine rootare present for most of its length, especiallylingually. The actual length of the R/C rootis 244. Apart from the Dmr and distal faceof the P4 that are almost completely pre-served, the P4 and M1 look like theirantimeres.

    The M2 has 4 main cusps, of which theMed is the dominant, a small Hld, and a C6made up of 2 cuspules. From largest tosmallest the cusp areas are: Med, Prd, Hyd,End, Hld, C6. There are wear facets andpolish on all cusps, and the buccal cusps areslightly flattened but with no dentine expo-sure. The Mlg runs from the shallow andpoorly delimited Fa to the crenulated Fc,where it disappears. Two secondary fissuresrun mesially from the tip of the Med towardsthe Fa and the Mlg, and others run pos-teriorly from close to the tip of the Medto the Fc and lingual groove. Secondaryfissures also run similarly down the distalcusps into the Fc, the lingual groove and theFp. The lingual and mesiobuccal groovesare continuous across the crown. Thelingual groove extends onto the lingual faceand terminates near the cervix. Themesiobuccal groove deeply incises thebuccal face, and terminates at a protostylidthat continues mesially around the Prd anddistally as a cingulum around the Hyd as far

    as a break on the MD corner. A small part ofthe mesial IPF is visible, but most is missingbecause of the broken chip of tooth. On thedistal margin of the tooth an irregularlyshaped distal IPF has two distinct parts.Both M3s were evidently erupted and incontact with the M2s.

    C: LI2. This I2 is complete except forchips of enamel lost along the edges of abreak running across the crown, and somebone along a crack across the root. Thetooth is lightly worn, exposing a ribbon ofdentine about 5 long and 05 wide on themesial incisive edge. The lateral two-fifths ofthe edge slopes downwards, away from theincisive wear plane at about 45. There ispolishing in the proximity of the occlusaledge on both the lingual and labial faces.The mesial margin of the tooth is fairlystraight, and the tooth expands slightly inwidth mesially from the cervix. The distalmargin flares out more substantially to makethis tooth 85 MD. The labial surface of theI2 is concave, with a hint of a distolabialgroove. The mesial surface has a reciprocalfacet for the central incisor. The lingualsurface is concave in both major directions.The basal tubercle is present but notaccentuated. The distal IPF is visible but notclearly demarcated. It is about 29 by 2. Theroot is strongly compressed MD with longi-tudinal grooves on both mesial and distalfaces. It is 16 long measured on the mesialsurface from the incisal angle to the root tip.

    D: RI2. This specimen preserves thelingual half of the crown; most of the labialsurface is broken away. In its preservedparts, this tooth is the mirror of the left one.

    E: RP3. This partial crown is missing awedge from the buccal face extending fromthe cervical margin most of the way to theapex, and another piece from the distalmargin. Enamel is preserved to the cervicalmargin only on the distolingual corner.There is no dentine exposure, but the ridgesand crests show polishing. The surface ofthe tooth shows perikymata which are worn

  • 283AUSTRALOPITHECUS ANAMENSIS

    away apically, most likely as the result ofantemortem wear. The tooth is oval in oc-clusal outline with a more tightly convexdistolingual portion. It has one central cusp.The mesial occlusal ridge joins a short Mmrthat encloses a small Fa. The transverse crestruns lingually for about 5 before it bifurcatesand sends a mesial branch to the cervix and adistal branch to join a Dmr. The distal oc-clusal ridge runs distally to join a short Dmrthat encloses a larger Fp. A portion of thedistal IPF can be seen on the Dmr adjacentto the break of the missing fragment. Notrace of the canine contact facet is apparent,although that area of tooth is preserved.

    F: RM3. This crown has lost the enamelaround the entire cervical margin; slightly solingually, about halfway up mesially andbuccally, and all the way to the occlusalsurface distally. No root is preserved. Theocclusal outline is a rounded rectangle, withwhat would have been a convex posteriormargin. It has four main cusps, of which thePrd is the largest and the others are subequalin area. All cusps are traversed by secondaryfissures, and accessory cuspules are visible inthe Fc. As on the M2, the mesiobuccalgroove is continuous across the central basinwith the lingual groove. The Mmr extendspartially around the Med. There are threedevelopmental pits around the Med andwear facets on both mesial cusps and on theHyd. The facet on the Hyd exposes dentine,and is associated with a large chip of enamelthat was broken from the buccal side of thiscusp during life. This happened in life,rather than post mortem, because this is theonly cusp with dentine exposure in a facet,its antimeric cusp has almost the full thick-ness of enamel left and the edges of thebroken enamel defect are smoothed over. Ifthis had occurred by post mortem rolling itwould also have abraded the edges of thewear facets, but these are still sharp. Asfor the M2, the Mlg terminates at the Fcafter meeting the continuous lingual andmesiobuccal grooves. The lingual groove

    extends to the break close to the cervix. TheV-shaped mesiobuccal groove deeply incisesthe buccal face.

    G: LM3. This is the buccal and distal por-tion of the left M3 crown. It is similar to itsantimere. The buccal surface of the toothretains almost the entire extent of its enamel,and has a less pronounced mesiobuccalgroove than its antimere. It shows a proto-stylid that extends mesially from the mesio-buccal groove. Distally, a cingulum bordersthe Hyd. Many cuspule-like vertical striationsindent the buccal and distal faces. Both pre-served cusps show wear, extending from theHyd into the central basin.

    H: LI1 crown. This crown is missing thecervical half of the lingual surface. A tinyportion of root is preserved on the mesio-labial corner. The crown is worn, exposinga ribbon of dentine about 05 wide. The facetfor the other I1 is an elongated oval, measur-ing about 40 long SI by 14 LaL, withweakly defined edges. The I2 facet is clearerand roughly circular, measuring about 2 indiameter. The labial surface is smoothly con-vex, with well-marked perikymata on the cer-vical half, but these have been worn off theincisive half. The lingual surface is almostflat to slightly concave, with light undulatingridges running from the wear plane towardsthe marginal tubercle. There are roughlysymmetrical mesial and distal groovesseparating similarly sized mesial and distalridges. The mesial and distal margins aresubparallel, so the tooth has a roughlyrectangular outline in lingual view, and doesnot splay out markedly from the cervix.

    I: 7 crown fragments (not figured).These fragments include parts of twoincisors, a canine, and three molars orpremolars. One is indeterminate.

    KNM-KP 30498L and R maxillaryfragments and associated maxillarydentition (Figure 7: GL not figured).

    This specimen was discovered washingdown the southern slope of a small hillock

  • 284 . . ET AL.

    Figure 7. KNM-KP 30498 associated maxillary dentition. (A) in labial, lingual, mesial and occlusal views,(B) in labial, lingual, mesial and occlusal views, (C) in distal and occlusal views, (D) in occlusal view,(E) in mesial and occlusal views, and (F) in occlusal view.

    65 m from the site of discovery of the typemandible, KNM-KP 29281 (Wynn, 2000,Figure 2). Apart from the initial isolatedteeth, the majority of these teeth wererecovered through screening. SpecimensKNM-KP 30505, which includes a molargerm, and KNM-KP 30942, tooth frag-ments, were also recovered in the screening.

    A: L premaxillary fragment (I1, rootI2). This is a complete I1 crown and root,along with maxillary bone lateral to it hous-ing just over half of the I2 root. The I1 crown

    is cracked and weathered, but the mor-phology is preserved. On the labial andmesial faces, cracks runs through the crownvertically from the root widening to about02 at the occlusal surface. The crown isheavily worn almost to the basal tubercle.Dentine exposure is 25 at its maximum LaLby 93 MD. Both the mesial and distalmargins of the crown flare out strongly fromthe cervix almost symmetrically, but thedistal margin slightly more so. The basaltubercle is swollen, and the Mmr and Dmr

  • 285AUSTRALOPITHECUS ANAMENSIS

    fade into it. There are traces of three lingualgrooves running into the tubercle from thewear facet. Both IPFs are indistinct due toweathering, but the distal one can be seenset distolingually on the Dmr. Mesial anddistal enamel lines are strongly concavetowards the occlusal surface. The lingualenamel line is mildly convex, but the labialone is damaged. The root measures 17 longfrom the cervical margin labially. The root is77 LaL and 68 MD at the cervix.

    Only 125 of the I2 root is preserved fromits apex, and its original length is estimatedto have been 18. It is oval at its brokensection, with only a faint distal groovetraversing its distal side. It measures about53 MD by 77 LaL at its break. Its apex isblunt, and the root appears to convergeupon the I1 root apically.

    B: RC/. This tooth is missing only theapex of its root, and the enamel at its distaledge obscuring any Dmr. The crown isweathered, and has a 02 wide crack runningLaL through its center. It flares out mesiallyand distally from the root, below its archedcervical margins. The crown is worn acrossthe tip, exposing a tear-dropped area ofdentine measuring 52 MD by 28 LaL thatslopes distally and lingually. The crown isasymmetrical, with the Mmr separated fromthe main cusp by a shallow marginal groove.This pronounced marginal ridge and mar-ginal groove continue across the occlusalsurface and faintly onto the labial surface,forming a prominence and concavity,respectively, in the occlusal outline in labialand lingual views. The labial surface is uni-formly convex, with perikymata exposednear its cervical margin. The lingual surfacehas a swollen cervical tubercle that is con-tinuous with the shallow mesial and distalmarginal grooves, and with the pronounced,rounded median lingual ridge that is locatedtowards the mesial edge of the toothimmediately adjacent to the mesial marginalgroove. Distal to the median lingual ridge,and inferior to the cervical swelling the

    lingual face of the tooth is flat. There is nodiscernible facet for the I2. The root is 91MD by 75 LaL at the cervix. The premolarfacet cannot be seen on the canine becauseof the missing enamel in this area.

    C: R maxillary fragment (P3). This is acompletely preserved crown, with partialroots surrounded by some maxillary bone.Part of the canine alveolus is preservedmesially, indicating the position of thispremolar in the maxilla. Much of the speci-men is weathered, obscuring the occlusalmorphology. The crown has two tiny expan-sion cracks running across its partially wornocclusal surface that would affect measure-ments minimally. It is a bicuspid tooth witha tall, conical Pa that occupies more thanhalf of the occlusal area, and a low roundedPr. There are indistinct mesial and distalgrooves adjacent to the rounded Mmr andDmr respectively. Wear has flattened bothcusps and there is a tiny area of dentineexposure on the tip of the Pa, but none onthe Pr. Ridges and crests are polished bywear. Both buccal and lingual faces slopeinwards towards their tips, but the buccalone slopes more strongly. The lingual sur-face is smoothly convex all around, but thebuccal face has slight mesial and distalgrooves and ridges. There is a strong mesio-cervical enamel extension of the buccal face.The crown flares out mesially and distallyfrom its root about equally, and bulgesjust below the cervical margin labially andlingually. The mesial IPF is set midway onthe mesial border; it is small but indistinctdue to weathering. The P3 has two roots,with distinct buccal and lingual roots. Thelingual one is missing only its apex, andmeasures 142 long as preserved, which isalmost all of its original length. It angleslingually from the crown and somewhatdistally. Only about 22 of the buccal root isleft. Part of the alveolus for P4 is visible, andabout 5 of the P4 root near its apex isadhered to the bone surrounding the P3

    roots.

  • 286 . . ET AL.

    D: L maxillary fragment (M3). This isa fragment of maxilla with no preservedcortex, and the lingual two-thirds of a M3

    crown with its roots embedded in themaxillary bone. The surface of the tooth isquite weathered. Enough of the crown ispreserved to show that it is an almostsymmetrical mirror copy of the other one(E), although the details of the cuspules arenot identical.

    E: R maxillary fragment (M3, rootM2). This is a complete M3, except forfragments of the enamel broken from thecervical margin lingually and distally. It hasa single root that is encased in maxillarybone on all but its distal sides. A sliver of thedistolingual root of M2 is preserved mesially.The occlusal outline of the M3 is a roundedtriangle, with the blunt apices mesio-lingually, mesiobuccally and distally, so it isformed by the two mesial cusps and anirregular set of distal cuspules. The occlusalsurface is lightly worn with flattening andpolishing of mesial cusps and ridges. The P


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