Caribbean Journal of Science, Vol. 29, No. 3-4, 153-164, 1993Copyright 1993 College of Arts and SciencesUniversity of Puerto Rico, Mayaguez

The Cuban Crocodile, Crocodylus rhombifer, from LateQuaternary Fossil Deposits on Grand Cayman

GARY S. MORGAN ,1 RICHARD FRANZ,1 AND RONALD I. CROMBIE

2

1Florida Museum of Natural History, University of Florida,Gainesville, Florida 32611

2Division of Reptiles and Amphibians, National Museum of Natural History,Smithsonian Institution, Washington, D.C. 20560

ABSTRACT . – Fossil remains of crocodiles have been recovered from six sites on Grand Cayman, a smallisland in the northwestern Caribbean Sea about 250 km south of Cuba. The three most productive fossilfaunas (Chisholm Cow Well, Crocodile Canal, and Furtherland Farms Cow Well) were deposited in aquaticdepositional environments, based on the presence of dark organic sediments and the predominance offreshwater and estuarine vertebrates. Radiocarbon dates of 860 ± 50 yBP and 375 ± 60 yBP obtained onpeat samples from the Crocodile Canal site confirm that crocodiles inhabited Grand Cayman until the lateHolocene, although they are no longer found there. The Grand Cayman fossil sample contains four nearlycomplete skulls that closely resemble modern specimens of the Cuban crocodile, Crocodylus rhombiferCuvier. The diagnostic cranial features they share include: comparatively short, broad, and deep rostrum;large orbits; strongly concave cranial roof and interorbital region; prominent ridges on dorsal margin oforbits and lateral edge of postorbital and squamosals, terminating in a rounded protuberance on pos-terolateral corner of squamosals; premaxillary/maxillary suture on palate transverse at level of first max-illary tooth; and 13 maxillary teeth. Most of the fossils in the extensive sample of C. rhombifer from GrandCayman represent juvenile and subadult individuals. The name of the Cayman Islands is probably derivedfrom the abundance of crocodiles prior to their local extinction during the last century.

INTRODUCTION

Morgan and Patton (1979) first reportedfossil crocodiles in the Cayman Islandsbased on a single tooth collected in 1976from a small cave at the eastern end ofGrand Cayman. In the past ten years, croc-odile fossils have been collected from fiveadditional sites on Grand Cayman. Thethree sites containing the richest samplesof crocodile bones, Chisholm Cow Well,Crocodile Canal, and Furtherland FarmsCow Well, are composed of dark, peaty,organic sediments that probably formed ina quiet estuarine or brackish depositionalenvironment such as a mangrove swampor coastal lagoon. The abundance of croc-odiles and the presence of several speciesof wading birds in the Grand Cayman sitesis unusual, as the vast majority of WestIndian vertebrate fossil deposits occur incaves and are dominated by terrestrial taxa(Morgan and Woods, 1986; Morgan, inpress).

At the invitation of the Mosquito Re-search and Control Unit and Natural Re-

sources Study (MRCU) of the Cayman Is-lands government, Gary Morgan andRichard Franz conducted a paleontologicalsurvey of the Cayman Islands in Januaryand February of 1986. Excavations at theChisholm Cow Well and Furtherland FarmsCow Well sites produced abundant fossilsof crocodiles and other vertebrates. Thecrocodile bones recovered from these twodeposits, as well as material from three ad-ditional sites, Crocodile Canal, ConnallyCow Well, and Prospect, form the basis forthe present report.

The Cayman Islands, including GrandCayman, Little Cayman, and Cayman Brat,are three small, low limestone islands lo-cated in the northwestern Caribbean Seabetween 19°15’N and 19°45’N latitude and79°42’W and 81°26’W longitude. They aresituated slightly more than 200 km fromboth Cuba to the north and Jamaica to thesoutheast, and about 500 km from the clos-est point in Central America.

Grand Cayman is the largest of the is-lands, with an area of 197 km2. Its maxi-mum elevation is about 20 m and more

153

154 G. S. MORGAN ET AL.

than half the island’s area is under 5 m.Low-lying areas are characterized bybrackish lagoons, mangrove swamps, andother swamp vegetative formations.

Although they are low and flat, the Cay-man Islands represent the projecting peaksof high submarine mountains located alongthe Cayman Ridge on the southern edgeof the North American plate. The CaymanIslands are surrounded by deep water inall directions. Depths of 1000 m or moreoccur between the Cayman Islands andboth the Greater Antilles and MiddleAmerica. Depths of nearly 2000 m havebeen recorded between Grand Cayman andLittle Cayman, and the narrow channel be-tween Cayman Brat and Little Cayman isalmost 1000 m deep. These depths precludeland connections during Pleistocene lowsea levels, either within the Cayman Is-lands or between the Caymans and otherland masses.

The following museums and institutionspossess specimens of fossil or extant croc-odiles from the West Indies that we ex-amined during this study. The standardabbreviation follows the name in paren-theses.

American Museum of Natural History(AMNH)

Cayman Islands National Museum (CINM)Florida Museum of Natural History—for-

merly the Florida State Museum (UF)Mosquito Research and Control Unit and

Natural Resources Study (MRCU)Museum of Comparative Zoology, Har-

vard University (MCZ)United States National Museum of Natural

History (USNM)

DESCRIPTION OF FOSSIL DEPOSITS

Fossil deposits in the Cayman Islands thathave yielded remains of crocodiles are re-stricted to Grand Cayman. With the excep-tion of one tooth from Crab Cave at theeastern end of the island (Morgan and Pat-ton, 1979), the fossils are preserved in darkbrown to black, highly organic, peaty sed-iments. The most abundant species pre-served in these organic sediments is theCuban crocodile, Crocodylus rhombifer Cu-vier, which is now extinct in the Cayman

Islands. In two deposits, the Chisholm CowWell and the Furtherland Farms Cow Well,the fossiliferous organic sediments weredeposited in small depressions or sink-holes in the limestone. These depressionsare called “cow wells” by residents becausethey are used as a source of drinking waterfor cattle, especially after the organic sed-iments are removed to deepen the holes.It is during the removal of these sedimentsthat fossils have been discovered.

The third major locality for fossil croc-odiles on Grand Cayman, Crocodile Canal,is different from the other two sites, sinceit did not form in a limestone depression.This site consists of a mangrove peat de-posit uncovered during the excavation ofa mosquito control canal. Although the cowwell deposits and the mangrove peatformed under different depositional con-ditions, they are similar in the high organ-ic content of the sediments and the abun-dance of C. rhombifer bones. These sites alsocontain bones of many other vertebrates,including freshwater and terrestrial forms.No strictly marine vertebrates have beenidentified from either deposit.

Brief descriptions of the fossil depositson Grand Cayman that have produced fos-sil crocodiles are provided below. The lat-itude and longitude are given for each ofthe fossil sites, along with the six-digit co-ordinates based on the 1000 meter Uni-versal Transverse Mercator Grid (Grid ZoneDesignation 17Q) taken from the 1:25,000topographic map series for the Cayman Is-lands, published in 1978 by the British Di-rectorate of Overseas Surveys. The firstthree digits are east coordinates and thelast three are north coordinates. The six-digit number is preceded by two letterscorresponding to the 100,000 m2 identifi-cation (MM is the designation for GrandCayman). More detailed locality data, fieldnotes, and photographs for these sites areavailable in the vertebrate paleontology lo-cality files of the Florida Museum of Nat-ural History. A map showing the locationof all vertebrate fossil sites on Grand Cay-man can be found in Morgan (in press).

Chisholm Cow Well (19°21’N, 81°13’W;MM765391). — The Chisholm Cow Well islocated about 0.3 km south of Grape Tree

FOSSIL CROCODILES FROM GRAND CAYMAN 155

Point and 1.8 km southwest of North Side.This site is only a few meters above sealevel and consists of a small depression orsinkhole in the limestone about 5 m long,3 m wide, and 1-2 m deep. The bones arepreserved in a dark, organic sediment atthe bottom of the sinkhole. The bones fromthe Chisholm Cow Well are predominant-ly those of the Cuban crocodile, Crocodylusrhombifer, along with much smaller sam-ples of the capromyid rodents Capromys andGeocapromys, the rock iguana Cyclura nubilaGray, and snakes. Bones were originallydiscovered at this site when sediments wereremoved from the cow well during the dryseason. The largest sample of bones fromthe Chisholm Cow Well was collected byRolin Chisholm and the late Ira Thompsonin the late 1970’s. One of us (GSM) exam-ined Thompson’s sample of fossils in April1980, which included several skulls andmandibles of C. rhombifer and a completeskull of Capromys. After Thompson’s death,his collection was obtained by the govern-ment of the Cayman Islands, and has beentransferred to the Cayman Islands NationalMuseum. Rolin Chisholm generously do-nated a representative sample of his col-lection from the site to the UF vertebratepaleontology collection. Rolin Chisholm,R. Franz, and G. S. Morgan conducted fur-ther excavations at the Chisholm Cow Wellin February 1986.

Connally Cow Well (19°21’N, 81°13’W;MM773391). — A single well preservedskull of Crocodylus rhombifer was found inthe Connally Cow Well, located a few me-ters above sea level 0.5 km southwest ofHutland. No other fossils are known fromthis site. This skull was obtained by theMRCU.

Crab Cave (19°18’N, 81°06’W; MM889338).— Crab Cave is located in East End on thenorth side of the main island road about0.7 km west of the Gorling Bluff Light-house. The small opening to the cave is atthe base of a 7-8 m high limestone ridgeparallel to and about 200 m inland fromthe south shore of the island. Crab Cave issmall and linear, barely 50 m in lengthwith no side passageways. The only pro-ductive sediment accumulation was locat-ed underneath a ledge about 4 m inside

the cave entrance. A test pit 2 m long, 1 mwide, and 0.5 m deep was dug under thisledge. Besides the single tooth of a croco-dile (Morgan and Patton, 1979), Crab Caveproduced fossils of Cyclura nubila, smallerlizards, two species of snakes, birds, bats,and rich samples of capromyid rodents(Morgan, in press). Crab Cave was exca-vated by H. G. McDonald, G. S. Morgan,and N. R. Thanz in March 1976 and by M.K. Langworthy and G. S. Morgan in April1980.

Crocodile Canal (19°19’N, 81°23’W;MM603363). — The Crocodile Canal site wasdiscovered in a mosquito control canalabout 3 km north of George Town. Thecanal was dug through a mangrove swampand is only slightly above sea level. Thebones were derived from a dark, highlyorganic peat deposit exposed in the sidesand bottom of the canal. Most of the boneswere obtained by soaking the peat andwashing the sediment through a windowscreen. The great majority of bones fromthis site are from small individuals of theCuban crocodile. Also present are Cycluranubila, the snakes Alsophis cantherigerus Bi-bron and Tretanorhinus variabilis Dumeriland Bibron, the clapper rail Rallus longi-rostris Boddaert, and Capromys. The Croc-odile Canal Site was originally discoveredby Edward and Robert Materne in 1979.Further excavations were conducted inApril 1980 by J. J. Belwood, M. K. Lang-worthy and G. S. Morgan.

Furtherland Farms Cow Well (19°19’N,81°08’W; MM853364). — The FurtherlandFarms Cow Well is located in a bananaplantation at the eastern end of the island,about 3 km north of Half Moon Bay andabout 10 m above sea level. This cow wellis actually a small water-filled cave about5 m across and 2-3 m deep. The sedimentswere removed so the cave could functionas a well, filling with rainwater which ispumped to irrigate the banana plants. Aswith the Crocodile Canal and ChisholmCow Well sites, the Furtherland Farms sed-iments are composed of dark brown toblackish organic peat containing numer-ous bones of Crocodylus rhombifer. T h eFurtherland Farms Cow Well has a morediverse terrestrial vertebrate fauna than the

156 G. S. MORGAN ET AL.

other two aquatically-derived organic fos-sil deposits. In addition to C. rhombifer, thevertebrate fauna is composed of Cyclura nu-bila, the lizard Anolis conspersus, the smallinsectivore Nesophontes, the capromyid ro-dents Capromys and Geocapromys; and therichest fossil avifauna recorded from GrandCayman, including the lizard cuckoo Sau-rothera merlini d’Orbigny, the Cuban crowCorvus nasicus Temminck, and a large sam-ple of the ibis Eudocimus sp. Although ra-diocarbon dates have not been obtainedfrom this site, the presence of several spec-imens of the introduced black rat Rattusrattus indicates that at least a portion of thedeposit is post-Columbian (<500 yBP). Asmall sample of bones from this site wasbrought to the MRCU by Mr. ReginaldKoster, a science teacher at the CaymanIslands High School, who obtained themfrom a student named Blair Smith. The sitewas rediscovered in February 1986 by G.S. Morgan, R. Franz, and J. Andresen, whoremoved a sizeable sample of bones. In Au-gust 1987, R. Franz and S. Franz screenedmore bones from the Furtherland Farmssediments.

Prospect (19°16’N, 81°20’W; MM645314).—A nearly complete skull with mandiblesand a partial postcranial skeleton of a sin-gle Crocodylus rhombifer were found in amangrove swamp just north of Prospect.The specimen was collected on the surfaceand appears to be quite recent, because thebones are white and unmineralized. Thisskeleton was found about 1980 by a Mrs.Pierce who gave it to Lear Grimmer. Mr.Grimmer subsequently donated the spec-imen to the UF vertebrate paleontologycollection.

Age of Fossil Deposits. — Two radiocarbon(14C) dates were obtained from samples ofmangrove peat from the Crocodile Canalsite (Morgan and Woods, 1986). One of thepeat samples contained crocodile bones andthe other was collected in direct associa-tion with crocodile remains. Both dateswere analyzed by the Smithsonian Insti-tution (SI) Radiocarbon Laboratory. Thedates are presented with a ± factor of onestandard deviation and the SI lab numbersin parentheses. The first sample (SI-5068),containing a tooth and an osteoderm of

Crocodylus rhombifer, was dated at 860 ± 50yBP. The second sample (SI-5069), contain-ing a femur of an undescribed extinct spe-cies of the capromyid rodent Capromys(Morgan, in press), yielded a date of 375± 60 yBP. Both peat samples were subjectto minor contamination from modernmangrove roots but there is no doubt thatthis deposit is late Holocener almost cer-tainly younger than 1000 yBP. The youn-ger date suggests a post-Columbian age,although there are no human artifacts orbones of Rattus present to confirm this. Asimilar but undated site on Grand Cayman,the Furtherland Farms Cow Well, containsC. rhombifer along with extinct species ofNesophontes, Capromys, and Geocapromys, inassociation with Rattus rattus. The close as-sociation of C. rhombifer with the intro-duced Rattus in the Furtherland Farms CowWell establishes a post-Columbian (<500yBP) age for this site.

SYSTEMATIC PALEONTOLOGY

Crocodylus rhombifer Cuvier, 1807Specimens Examined. — Only cranial and

mandibular elements are listed separatelyhere. More detailed information on thepostcranial material is available in the ver-tebrate paleontology collection of the Flor-ida Museum of Natural History.

Chisholm Cow Well: nearly completeskull (UF 80000), associated premaxilla andmaxilla (UF 128085), associated frontals (UF128086), 2 ectopterygoids (UF 128069,128087), prefrontal (UF 128070), completemandible (UF 128065), associated angularand surangular (UF 128066), angular (UF128088), surangular (UF 128067), articular(UF 128068), 35 isolated teeth (UF 128089),43 assorted postcranial elements (UF128071-128084, 128090-128098). Mini-mum number of individuals representedin sample is 5.

Connally Cow Well: nearly completeskull (original in MRCU; cast-UF 128064).

Crab Cave: 1 tooth (UF 22739).Crocodile Canal: nearly complete skull

(USNM 216197 ), 2 premaxillae (UF 61101-61102), 2 maxillae (UF 61103-61104), 1frontal (UF 61 162), associated jugal and lac-rimal (UF 61105), associated jugal and qua-

FOSSIL CROCODILES FROM GRAND CAYMAN 157

dratojugal (UF 61106), 2 pterygoids (UF61107-61108), 3 ectopterygoids (UF 61109-61111), 3 dentaries (UF 61112-61114), 2 an-gulars (UF 61115-61116), 4 surangulars (UF61117-61119, 61163), 7 articulars (UF61120-61126); 69 isolated teeth (UF 61142,61164, 61165), 81 assorted postcranial ele-ments (UF 61127-61145, 61166-61171).Minimum number of individuals repre-sented in sample is 6.

Furtherland Farms Cow Well: partialcranial roof (UF 128128), 2 maxillae (UF128134, 128135), 3 lacrimals (UF 128101,128136, 128137), squamosal (UF 128138),dentary (UF 128139), 2 splenials (UF 128102,128129), articular (UF 128140), 12 isolatedteeth (UF 128111, 128141), 80 assorted post-cranial elements (UF 128102-128110,128109-128127, 128130-128133, 128142-128159). Minimum number of individualsrepresented in sample is 3.

Prospect: nearly complete skull, rightand left mandibles, humerus, femur, andabout ten vertebrae, all from a single in-dividual (UF 65800).

Modern Distribution. — The Cuban croco-dile, Crocodylus rhombifer, is restricted toCuba, Isla de Pines, and the Archipielagode los Canarreos (Varona, 1966; Schwartzand Henderson, 1991). Historical evidenceand fossils confirm that C. rhombifer wasonce more widely distributed in Cuba (Va-rona, 1966, 1984).

Fossil Record. — Varona (1984) reportedfossils of Crocodylus rhombifer from threelocalities in central Cuba: the springs atCiego Montero, a fissure in the Sierra deJatibonico, and the caves of Cueiba in theSierra de Remedios. The fossil species C.pristinus, described by Leidy (1868) basedon a single damaged vertebra from CiegoMontero, was considered a synonym of C.rhombifer by Varona (1984). Varona (1966)described a second extinct species fromCuba, C. antillensis, from a fossil deposit inCueva Lamas near Santa Fe on the north-ern coast of the island just west of Havana.Morgan and Patton (1979) reported a sin-gle tooth of Crocodylus sp. from Crab Caveon Grand Cayman.

Description and Comparisons. — The im-pressive sample of crocodile fossils nowavailable from Grand Cayman includes four

nearly complete skulls along with manyisolated cranial elements, mandibles, andpostcranial bones (Figs. 1-3). The excellentpreservation of the Grand Cayman fossilspermits detailed comparisons of theseskulls with those of the two species of Croc-odylus now found in the West Indies, C.acutus and C. rhombifer, as well as the Mid-dle American species, C. moreletii. To elim-inate morphological differences related toontogenetic factors, only skulls of approx-imately the same size as the Grand Caymanfossils were used for comparisons. Croco-dylus acutus is a widespread species occur-ring in southernmost Florida, throughoutmost of the Greater Antilles, and from bothcoasts of Mexico south to northern SouthAmerica. Crocodylus moreletii is restricted tothe Gulf and Caribbean drainages of Mid-dle America from central Tamaulipas Prov-ince in Mexico south to Belize and Gua-temala.

Varona (1966) compared the skulls ofCrocodylus acutus and C. rhombifer, noting anumber of characters that readily separatethe two species. We compared these samefeatures in two skulls of C. moreletii. TheGrand Cayman fossils closely resemble C.rhombifer. Unless otherwise noted, all char-acters discussed here for modern Cubanspecimens of C. rhombifer pertain to theGrand Cayman fossils as well. Crocodylusrhombifer skulls have a comparativelyshorter, broader, and deeper snout than C.acutus, which has a narrower and more flat-tened rostrum. The rostrum of C. rhombiferis particularly deep just anterior to the or-bits. C. moreletii is somewhat intermediatebetween these two species in the length ofthe snout, but the depth of the rostrum ismore like that of C. acutus. The premaxillaof the Cuban crocodile also is broader,shorter, and deeper than that of C. acutus.In C. rhombifer and C. moreletii, the dorsalsurface of the premaxilla along the midlinebears a short, blunt process that extends nofarther posteriorly than the second max-illary tooth. The premaxilla of C. acutus hasa narrow, elongated, triangular-shapedprocess extending posteriorly to the levelof the third or fourth maxillary tooth. Thesethree species also differ in the shape of thepremaxillary/maxillary suture on the pal-

158 G. S. MORGAN ET AL.

FIG. 1. Fossil skull of Crocodylus rhombifer (UF 80000) from Chisholm Cow Well, Grand Cayman, in dorsal(A), ventral (B), and right lateral (C) views. Scale bar equals 25 mm.

FOSSIL CROCODILES FROM GRAND CAYMAN 159

atal surface. The suture is transverse at thelevel of the first maxillary tooth in C. rhom-bifer and C. moreleti, while in C. acutus it isW-shaped and extends posteriorly to thethird maxillary tooth. Compared to C. acu-tus, the distance between the tip of the

snout and the anterior edge of the externalnarial opening is reduced in C. rhombiferand C. moreletii. In C. acutus, the anteriorportion of the premaxilla is longer and thenarial opening begins farther posteriorly,

In C. rhombifer and the Grand Cayman

160 G. S. MORGAN ET AL.

FIG. 3. Fossil skull of Crocodylus rhombifer (MRCU/CINM uncat., cast-UF 128064) from Connally Cow Well,Grand Cayman, in dorsal (A) and ventral (B) views. Scale bar equals 25 mm.

fossils, the cranial roof, composed of thefrontals, postorbital, squamosals, and pa-rietals, is markedly concave along the mid-line in the region of the dorsal temporalopenings (Figs. 1–3). The lateral edges ofthe cranial roof are strongly upraised,forming prominent ridges on the postor-bital and squamosals. There is a strongrounded protuberance on the posterolat-eral corner of the squamosal. Crocodylusacutus and C. moreletii have a flat cranialroof and the squamosal protuberances areabsent. The region between the orbits,principally the frontals, is deeply concavein the Cuban crocodile and the lateral edg-es form a strong raised ridge on the inter-nal margin of the orbits. The interorbital

region in C. acutus and C. moreletii is onlyslightly concave and the ridges on the in-ner margin of the orbits are weakly de-veloped. The combination of a deepersnout, elevated cranial roof, and more con-stricted interorbital region gives C. rhom-bifer a noticeably larger orbit than C. acutusor C. moreletii.

Modern skulls of C. rhombifer have 13(sometimes 12) maxillary teeth. Seven fos-sils from Grand Cayman have the completemaxilla preserved on at least one side, allwith 13 teeth. All specimens of C. acutusand C. moreletii examined have 14 maxillaryteeth. The third largest tooth in the den-tary (after the 4th and 1st) is the 10th toothin C. rhombifer, but is the 11th in C. acutus

I

FOSSIL CROCODILES FROM GRAND CAYMAN 161

TABLE 1. Measurements (in mm) of fossil Crocodylus rhombifer skulls from Grand Cayman.

ConnallyCow Well

Chisholm MRCU/CINMProspect Cow Well UF 128064 Crocodile CanalUF 65800 UF 80000 (CAST) USNM 216197

Total length of skull(premaxilla-quadrate) 305 255 247 251

Length of skull(premaxilla-squamosal) 283 236 230 233

Length of snout (premaxilla-anterior edge of orbits) 175 147 144 139

Length of premaxilla 58 47 49 48Length of maxilla 156 133 128 129Length of maxillary toothrow 148 127 121 125Breadth of premaxilla — 1

53 53 — 1

Breadth of snout(at 5th maxillary tooth) 100 71 73 72

Breadth of snout(at anterior edge of orbits) 127 88 96 90

Interorbital breadth 31 22 23 22Breadth of cranial roof

(at anterior edge) 76 59 56 57Breadth of cranial roof

(at posterior edge) 104 79 75 75Breadth of skull (at quadrate-

quadratojugal suture) 163 119 — 1

117

1 Measurements not taken because of damage to the fossils.

and C. moreletii. In summary, no charactersreadily distinguish the Cayman crocodilesfrom Cuban C. rhombifer of similar size.

Measurements. — Although large individ-uals of Crocodylus rhombifer are now rare inCuba due to overhunting, historical evi-dence and the fossil record demonstratethat this species can reach a very large size.Gundlach (1880) mentioned a specimen17.5 feet (5.3 m) long. Adults of this speciesnow are generally less than 3.5 m. We mea-sured several fossils of C. rhombifer in theAMNH from Ciego Montero in Cuba thatmust have come from enormous individ-uals, including a skull 677 mm long and amandible 818 mm in length. Comparisonswith modern crocodilian skulls (Thorb-jarnson and McIntosh, 1987) suggest thatthese fossils came from animals over 5 min length.

Comparative measurements of the fourmost complete skulls of C. rhombifer fromGrand Cayman are presented in Table 1.The largest skull (Prospect specimen) is 305

mm long. The skulls from the ChisholmCow Well, Connally Cow Well, and Croc-odile Canal sites are smaller, ranging from247-255 mm. Most of the skulls and post-cranial elements of C. rhombifer from GrandCayman appear to represent juvenile orsubadult individuals (C. Brochu, pers.comm.).

Comparative Material Examined. — Allcomparative specimens consisted of mod-ern skulls, with the exception of severalfossil skulls from Cuba. The country of or-igin, number of specimens examined, andthe museum collection abbreviation areprovided for the comparative material rep-resenting each of the three species. Croc-odylus rhombifer: Cuba (1 AMNH, 1 MCZ,1 UF); fossil skulls, Ciego Montero, Cuba(4 AMNH); C. acutus: Florida (6 UF), Do-minican Republic (1 UF), Haiti (2 UF), Cay-man Islands, Little Cayman (1 MCZ), Ja-maica (1 AMNH), Mexico (1 MCZ, 1USNM); C. moreletii: Mexico (1 UF, 1USNM).

162 G. S. MORGAN ET AL.

D ISCUSSION

Grant (1940) and Morgan and Patton(1979) summarized the historical literatureon the occurrence of crocodiles in the Cay-man Islands. Several quotations cited bythem are repeated here. The earliest knownreference to crocodiles in the Cayman Is-lands was in Walter Bigges’ 1589 narrativeon one of Sir Frances Drake’s Caribbeanvoyages. According to Bigges, on the 20thday of April 1586, Sir Frances Drake’s fleet,“. . . fell with two islands called Caimanes,where we refreshed ourselves with manyallagartas and greate turtoises, being veryugly and fearefull beasts to behold, butwere made good meate to eate . . .“ Bigges’term allagartas (also alagarto) is an earlierEnglish spelling of alligator and is derivedfrom the Spanish el lagarto. In the earlyEnglish historical literature from the WestIndies, alligator or its prior equivalent wasoften used as a general term for crocodil-ians. Bigges’ references to two islands in-dicates that Drake visited Little Caymanand Cayman Brat.

The next reference to crocodiles in theCayman Islands was in 1642 or 1643 by aCaptain William Jackson (from Grant 1940:3) who stated, “. . . ye island of Chimanos[apparently Grand Cayman] . . . this placeis low land and all rockye, and there beeother two Islands of ye same name andQuallitie [Little Cayman and Cayman Brat],being by ye Spanyards called Chimanos,from ye multitude of Alligators here foundwhich are Serpents, if not resembling yeCrocodiles of Egypt.” In his history of Ja-maica, Edward Long (1774:875) noted that,“. . . the crocodile . . . is found at GrandCaymanas . . . .“

According to Grant (1940), the first her-petological collection from the Cayman Is-lands was made on Grand Cayman in 1886by W. B. Richardson and reported by Gar-man (1887). In discussing the occurrenceof crocodiles on Grand Cayman, Garmanstated (1887:276), “Mr. Richardson statesthat the natives reported a crocodile in theswamps. ” The following year Garman(1888) reported on a collection made by C.J. Maynard on Little Cayman and CaymanBrat. Garman quoted from Maynard’s field

notes (1888:101), “Two species of croco-diles have been taken on this island [LittleCayman] and one on Cayman Brat. I [May-nard] saw but a portion of one specimen.The natives assured me the species weresimilar to those found in Cuba. ” In refer-ence to Garman’s records, Barbour (1914:345) stated, “The species referred to aredoubtless C. rhombifer and C. americanus [=C.acutus]. Whether they are resident on theCayman Group or whether they only reachthe islands occasionally by swimmingwould be well worth ascertaining defi-nitely.” Crocodiles apparently inhabitedthe three Cayman Islands until at least thelate nineteenth century. Individual croc-odiles have been reported sporadicallywithin the last 50 years, including a spec-imen of Crocodylus acutus captured alongthe southern coast of Little Cayman in 1939(Grant, 1940) and an unknown species ofcrocodile captured on Cayman Brat in the1950’s (Seidel and Franz, in press).

A radiocarbon date of 860 yBP from theCrocodile Canal Site establishes the pres-ence of Crocodylus rhombifer on Grand Cay-man in pre-Columbian times. The secondradiocarbon date of 375 yBP from the Croc-odile Canal Site and the presence of Rattusrattus in association with C. rhombifer in theFurtherland Farms Cow Well, clearly in-dicate that Cuban crocodiles inhabitedGrand Cayman when the Cayman Islandswere discovered by Columbus in 1503.

The discovery of fossil crocodile bonesfrom Grand Cayman may have some bear-ing on how the Cayman Islands werenamed. These islands are called Islas Cai-man in Spanish. The Amerindian word cai-man has been incorporated into the Span-ish language as a general term for allcrocodilians, and is the local Cuban namefor Crocodylus acutus (DeSola, 1930; Varona,1966). The prior abundance of Crocodylusrhombifer on Grand Cayman strongly sug-gests that the Cayman Islands were namedfor their formerly resident crocodiles.

The occurrence on Grand Cayman ofCrocodylus rhombifer rather than the morewidespread C. acutus is puzzling, particu-larly considering that C. acutus preferscoastal marine and brackish-water habi-tats, while C. rhombifer inhabits freshwater

FOSSIL CROCODILES FROM GRAND CAYMAN 163

marshes and swamps in Cuba (DeSola, 1930;Varona, 1966). Large portions of GrandCayman are below 5 m in elevation andare characterized by mangrove swamps,brackish lagoons, and other habitats fa-vored by C. acutus. The occurrence of C .rhombifer fossils in mangrove swamps intwo localities on Grand Cayman suggeststhat this species may have occupied a wid-er variety of habitats than it does presently.Furthermore, to reach Grand Cayman fromsouthern Cuba, individuals of C. rhombiferwould have to cross 250 km of open ocean,a difficult feat for an animal supposedlyrestricted to freshwater.

There is little doubt that Crocodylus rhom-bifer was a breeding resident on Grand Cay-man, based on the large sample sizes offossils in the Chisholm Cow Well, Croco-dile Canal, and Furtherland Farms CowWell sites, as well as the presence of nu-merous bones belonging to hatchlings orvery small individuals. The evidence forC. rhombifer on Little Cayman and CaymanBrat is much less convincing. Except forone museum specimen of C. acutus f romLittle Cayman, the occurrence of croco-diles on these two islands is based on in-conclusive sight records.

The disappearance of crocodiles andmany other species of vertebrates from theCayman Islands during the last 500 yearsprobably resulted from a combination ofhuman-caused habitat destruction and pre-dation (Morgan and Woods, 1986; Morgan,in press). Among the many extinct and ex-tirpated vertebrates from the Cayman Is-lands, only the crocodile is mentioned inthe historical literature. Numerous refer-ences from the sixteenth century onwardconfirm that crocodiles inhabited the Cay-man Islands until at least the late nine-teenth century.

Acknowledgments. — We are especiallygrateful to the many people who have as-sisted us in collecting or obtaining fossilcrocodile specimens from Grand Cayman,including Jack Andresen, Jacqueline Bel-wood, Nina Thanz Borremans, Rolin Chis-holm, J. E. Davies, Shelley Franz, LearGrimmer, Reginald Koster, Margaret Lang-worthy, Edward and Robert Materne, Greg

McDonald, Paul Moler, and Blair Smith.Rolin Chisholm generously donated a sam-ple of crocodile fossils, including a com-plete skull and mandibles, from GrandCayman to the Florida Museum of NaturalHistory and Edward Materne donated acomplete fossil crocodile skull and otherbones to the National Museum of NaturalHistory, Smithsonian Institution. In 1980the late Ira Thompson kindly allowed usto examine his extensive collection of croc-odile fossils from Grand Cayman, which isnow housed in the Cayman Islands Na-tional Museum. Jose Ottenwalder and JohnThorbjarnarson provided information onextant Caribbean crocodiles . KennethDodd, Wayne King, and Perran Ross madehelpful comments on an earlier draft of themanuscript. GSM and RF extend theirthanks to the government of the CaymanIslands, as well as J. E. Davies and theMRCU, for funding they received to con-duct a paleontological and herpetologicalsurvey of the Cayman Islands in January1986. Dr. Davies and his staff at the Mos-quito Research and Control Unit and Na-tional Resources Study in George Town,Grand Cayman have assisted us in allphases of our field research in the CaymanIslands. This is University of Florida Con-tribution to Paleontology Number 406.

LITERATURE CITED

Barbour, T. 1914. A contribution to the zoogeogra-phy of the West Indies, with especial reference toamphibians and reptiles. Mem. Mus. Comp. Zool.44(2):209-359.

DeSola, C. R. 1930. The Cuban crocodile, an accountof the species Crocodylus rhombifer Cuvier, withnotes on its life history. Copeia 1930(3):81-83.

Garman, S. 1887. On the reptiles and batrachians ofGrand Cayman. Proc. Amer. Phil. Soc. 24:273-277.

———. 1888. Reptiles and batrachians from the Cay-mans and from the Bahamas. Bull. Essex Inst. 20:101-113.

Grant, C. 1940. The herpetology of the Cayman Is-lands. Bull. Inst. Jamaica, Sci. Ser. 2:1-65.

Gundlach, J. 1880. Contribucion a la erpetologia deCuba. Imp. G. Montiel, La Habana. 99 pp.

Leidy, J. 1868. Notice of some vertebrate remainsfrom the West Indian islands. Proc. Acad. Nat. Sci.,Philadelphia. pp. 178-180.

Long, E. 1774. The history of Jamaica. London (3vols.).

Morgan, G. S. In press. Late Quaternary fossil ver-tebrates from the Cayman Islands. In J. E. Daviesand M. Brunt (eds.), Biogeography and ecology of

164 G. S. MORGAN ET AL.

the Cayman Islands. Monographiae Biologicae,Kluwer Academic Publishers, Dordrecht, Neth-erlands.

———, and T. H. Patton. 1979. On the occurrenceof Crocodylus (Reptilia, Crocodilidae) in the Cay-man Islands, British West Indies. J. Herp. 13(3):289-292.

———, and C. A. Woods. 1986. Extinction and thezoogeography of West Indian land mammals. Biol.J. Linnean Soc. 28:167-203.

Schwartz, A., and R. W. Henderson. 1991. Amphib-ians and reptiles of the West Indies. University ofFlorida Press, Gainesville, Florida. 720 pp.

Seidel, M. E., and R. Franz. In press. The amphibians

and reptiles of the Cayman Islands. In J. E. Daviesand M. Brunt (eds.), Biogeography and ecology ofthe Cayman Islands. Monographiae Biological,Kluwer Academic Publishers, Dordrecht, Neth-erlands.

Thorbjarnarson, J. B., and P. E. McIntosh. 1987. Noteson a large Melanosuchus niger skull from Bolivia.Herp. Rev. 18(3):49, 52.

Varona, L. S. 1966. Notas sobre los crocodilidos deCuba y descripcion de una nueva especie del Pleis-toceno. Poeyana, ser. A, No. 16:1-34.

———. 1984. Los crocodilos fosiles de Cuba (Rep-tilia: Crocodylidae). Carib. J. Sci. 20(1-2):13-18.