The Cuban Crocodile, Crocodylus Rhombifer, from Late Quaternary Fossil Deposits on Grand Cayman

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

1 1 2 G ARY S. MORGAN, RICHARD FRANZ, AND RONALD I. CROMBIE

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 small island in the northwestern Caribbean Sea about 250 km south of Cuba. The three most productive fossil faunas (Chisholm Cow Well, Crocodile Canal, and Furtherland Farms Cow Well) were deposited in aquatic depositional environments, based on the presence of dark organic sediments and the predominance of freshwater and estuarine vertebrates. Radiocarbon dates of 860 ± 50 yBP and 375 ± 60 yBP obtained on peat samples from the Crocodile Canal site confirm that crocodiles inhabited Grand Cayman until the late Holocene, although they are no longer found there. The Grand Cayman fossil sample contains four nearly complete skulls that closely resemble modern specimens of the Cuban crocodile, Crocodylus rhombifer Cuvier. 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 of orbits 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 maxillary tooth; and 13 maxillary teeth. Most of the fossils in the extensive sample of C. rhombifer from Grand Cayman represent juvenile and subadult individuals. The name of the Cayman Islands is probably derived from the abundance of crocodiles prior to their local extinction during the last century.

sources Study (MRCU) of the Cayman Is- INTRODUCTION lands government, Gary Morgan and Morgan and Patton (1979) first reported Richard Franz conducted a paleontological fossil crocodiles in the Cayman Islands survey of the Cayman Islands in January based on a single tooth collected in 1976 and February of 1986. Excavations at the from a small cave at the eastern end of Chisholm Cow Well and Furtherland Farms Grand Cayman. In the past ten years, croc- Cow Well sites produced abundant fossils odile fossils have been collected from five of crocodiles and other vertebrates. The additional sites on Grand Cayman. The crocodile bones recovered from these two three sites containing the richest samples deposits, as well as material from three ad- of crocodile bones, Chisholm Cow Well, ditional sites, Crocodile Canal, Connally Crocodile Canal, and Furtherland Farms Cow Well, and Prospect, form the basis for Cow Well, are composed of dark, peaty, the present report. organic sediments that probably formed in The Cayman Islands, including Grand a quiet estuarine or brackish depositional Cayman, Little Cayman, and Cayman Brat, environment such as a mangrove swamp are three small, low limestone islands lo- or coastal lagoon. The abundance of croc- cated in the northwestern Caribbean Sea odiles and the presence of several species between 19°15’N and 19°45’N latitude and of wading birds in the Grand Cayman sites 79°42’W and 81°26’W longitude. They are is unusual, as the vast majority of West situated slightly more than 200 km from Indian vertebrate fossil deposits occur in both Cuba to the north and Jamaica to the caves and are dominated by terrestrial taxa southeast, and about 500 km from the clos- (Morgan and Woods, 1986; Morgan, in est point in Central America. press). Grand Cayman is the largest of the is- At the invitation of the Mosquito Re- lands, with an area of 197 km2. Its maxi- search and Control Unit and Natural Re- 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. Islands. In two deposits, the Chisholm Cow Low-lying areas are characterized by Well and the Furtherland Farms Cow Well, brackish lagoons, mangrove swamps, and the fossiliferous organic sediments were other swamp vegetative formations. deposited in small depressions or sink- Although they are low and flat, the Cay- holes in the limestone. These depressions man Islands represent the projecting peaks are called “cow wells” by residents because of high submarine mountains located along they are used as a source of drinking water the Cayman Ridge on the southern edge for cattle, especially after the organic sed- of the North American plate. The Cayman iments are removed to deepen the holes. Islands are surrounded by deep water in It is during the removal of these sediments all directions. Depths of 1000 m or more that fossils have been discovered. occur between the Cayman Islands and The third major locality for fossil croc- both the Greater Antilles and Middle odiles on Grand Cayman, Crocodile Canal, America. Depths of nearly 2000 m have is different from the other two sites, since been recorded between Grand Cayman and it did not form in a limestone depression. Little Cayman, and the narrow channel be- This site consists of a mangrove peat de- tween Cayman Brat and Little Cayman is posit uncovered during the excavation of almost 1000 m deep. These depths preclude a mosquito control canal. Although the cow land connections during Pleistocene low well deposits and the mangrove peat sea levels, either within the Cayman Is- formed under different depositional con- lands or between the Caymans and other ditions, they are similar in the high organ- land masses. ic content of the sediments and the abun- The following museums and institutions dance of C. rhombifer bones. These sites also possess specimens of fossil or extant croc- contain bones of many other vertebrates, odiles from the West Indies that we ex- including freshwater and terrestrial forms. amined during this study. The standard No strictly marine vertebrates have been abbreviation follows the name in paren- identified from either deposit. theses. Brief descriptions of the fossil deposits on Grand Cayman that have produced fos- American Museum of Natural History sil crocodiles are provided below. The lat- (AMNH) itude and longitude are given for each of Cayman Islands National Museum (CINM) the fossil sites, along with the six-digit co- Florida Museum of Natural History—for- ordinates based on the 1000 meter Uni- merly the Florida State Museum (UF) versal Transverse Mercator Grid (Grid Zone Mosquito Research and Control Unit and Designation 17Q) taken from the 1:25,000 Natural Resources Study (MRCU) topographic map series for the Cayman Is- Museum of Comparative Zoology, Har- lands, published in 1978 by the British Di- vard University (MCZ) rectorate of Overseas Surveys. The first United States National Museum of Natural three digits are east coordinates and the History (USNM) last three are north coordinates. The six- digit number is preceded by two letters D ESCRIPTION OF FOSSIL D EPOSITS corresponding to the 100,000 m2 identifi- Fossil deposits in the Cayman Islands that cation (MM is the designation for Grand have yielded remains of crocodiles are re- Cayman). More detailed locality data, field stricted to Grand Cayman. With the excep- notes, and photographs for these sites are tion of one tooth from Crab Cave at the available in the vertebrate paleontology lo- eastern end of the island (Morgan and Pat- cality files of the Florida Museum of Nat- ton, 1979), the fossils are preserved in dark ural History. A map showing the location brown to black, highly organic, peaty sed- of all vertebrate fossil sites on Grand Cay- iments. The most abundant species pre- man can be found in Morgan (in press). served in these organic sediments is the Chisholm Cow Well (19°21’N, 81°13’W; Cuban crocodile, Crocodylus rhombifer Cu- MM765391). — The Chisholm Cow Well is vier, which is now extinct in the Cayman located about 0.3 km south of Grape Tree FOSSIL CROCODILES FROM GRAND CAYMAN 155

Point and 1.8 km southwest of North Side. the cave entrance. A test pit 2 m long, 1 m This site is only a few meters above sea wide, and 0.5 m deep was dug under this level and consists of a small depression or ledge. Besides the single tooth of a croco- sinkhole in the limestone about 5 m long, dile (Morgan and Patton, 1979), Crab Cave 3 m wide, and 1-2 m deep. The bones are produced fossils of Cyclura nubila, smaller preserved in a dark, organic sediment at lizards, two species of snakes, birds, bats, the bottom of the sinkhole. The bones from and rich samples of capromyid rodents the Chisholm Cow Well are predominant- (Morgan, in press). Crab Cave was exca- ly those of the Cuban crocodile, Crocodylus vated by H. G. McDonald, G. S. Morgan, rhombifer, along with much smaller sam- and N. R. Thanz in March 1976 and by M. ples of the capromyid rodents Capromys and K. Langworthy and G. S. Morgan in April Geocapromys, the rock iguana Cyclura nubila 1980. Gray, and snakes. Bones were originally Crocodile Canal (19°19’N, 81°23’W; discovered at this site when sediments were MM603363). — The Crocodile Canal site was removed from the cow well during the dry discovered in a mosquito control canal season. The largest sample of bones from about 3 km north of George Town. The the Chisholm Cow Well was collected by canal was dug through a mangrove swamp Rolin Chisholm and the late Ira Thompson and is only slightly above sea level. The in the late 1970’s. One of us (GSM) exam- bones were derived from a dark, highly ined Thompson’s sample of fossils in April organic peat deposit exposed in the sides 1980, which included several skulls and and bottom of the canal. Most of the bones mandibles of C. rhombifer and a complete were obtained by soaking the peat and skull of Capromys. After Thompson’s death, washing the sediment through a window his collection was obtained by the govern- screen. The great majority of bones from ment of the Cayman Islands, and has been this site are from small individuals of the transferred to the Cayman Islands National Cuban crocodile. Also present are Cyclura Museum. Rolin Chisholm generously do- nubila, the snakes Alsophis cantherigerus Bi- nated a representative sample of his col- bron and Tretanorhinus variabilis Dumeril lection from the site to the UF vertebrate and Bibron, the clapper rail Rallus longi- paleontology collection. Rolin Chisholm, rostris Boddaert, and Capromys. The Croc- R. Franz, and G. S. Morgan conducted fur- odile Canal Site was originally discovered ther excavations at the Chisholm Cow Well by Edward and Robert Materne in 1979. in February 1986. Further excavations were conducted in Connally Cow Well (19°21’N, 81°13’W; April 1980 by J. J. Belwood, M. K. Lang- MM773391). — A single well preserved worthy and G. S. Morgan. skull of Crocodylus rhombifer was found in Furtherland Farms Cow Well (19°19’N, the Connally Cow Well, located a few me- 81°08’W; MM853364). — The Furtherland ters above sea level 0.5 km southwest of Farms Cow Well is located in a banana Hutland. No other fossils are known from plantation at the eastern end of the island, this site. This skull was obtained by the about 3 km north of Half Moon Bay and MRCU. about 10 m above sea level. This cow well Crab Cave (19°18’N, 81°06’W; MM889338). is actually a small water-filled cave about — Crab Cave is located in East End on the 5 m across and 2-3 m deep. The sediments north side of the main island road about were removed so the cave could function 0.7 km west of the Gorling Bluff Light- as a well, filling with rainwater which is house. The small opening to the cave is at pumped to irrigate the banana plants. As the base of a 7-8 m high limestone ridge with the Crocodile Canal and Chisholm parallel to and about 200 m inland from Cow Well sites, the Furtherland Farms sed- the south shore of the island. Crab Cave is iments are composed of dark brown to small and linear, barely 50 m in length blackish organic peat containing numer- with no side passageways. The only pro- ous bones of Crocodylus rhombifer. The ductive sediment accumulation was locat- Furtherland Farms Cow Well has a more ed underneath a ledge about 4 m inside diverse terrestrial vertebrate fauna than the 156 G. S. MORGAN ET AL. other two aquatically-derived organic fos- Crocodylus rhombifer, was dated at 860 ± 50 sil deposits. In addition to C. rhombifer, the yBP. The second sample (SI-5069), contain- vertebrate fauna is composed of Cyclura nu- ing a femur of an undescribed extinct spe- bila, the lizard Anolis conspersus, the small cies of the capromyid rodent Capromys insectivore Nesophontes, the capromyid ro- (Morgan, in press), yielded a date of 375 dents Capromys and Geocapromys; and the ± 60 yBP. Both peat samples were subject richest fossil avifauna recorded from Grand to minor contamination from modern Cayman, including the lizard cuckoo Sau- mangrove roots but there is no doubt that

rothera merlini d’Orbigny, the Cuban crow this deposit is late Holocener almost cer- Corvus nasicus Temminck, and a large sam- tainly younger than 1000 yBP. The youn- ple of the ibis Eudocimus sp. Although ra- ger date suggests a post-Columbian age, diocarbon dates have not been obtained although there are no human artifacts or from this site, the presence of several spec- bones of Rattus present to confirm this. A imens of the introduced black rat Rattus similar but undated site on Grand Cayman, rattus indicates that at least a portion of the the Furtherland Farms Cow Well, contains deposit is post-Columbian (<500 yBP). A C. rhombifer along with extinct species of small sample of bones from this site was Nesophontes, Capromys, and Geocapromys, in brought to the MRCU by Mr. Reginald association with Rattus rattus. The close as- Koster, a science teacher at the Cayman sociation of C. rhombifer with the intro- Islands High School, who obtained them duced Rattus in the Furtherland Farms Cow from a student named Blair Smith. The site Well establishes a post-Columbian (<500 was rediscovered in February 1986 by G. yBP) age for this site. S. Morgan, R. Franz, and J. Andresen, who removed a sizeable sample of bones. In Au- SYSTEMATIC PALEONTOLOGY gust 1987, R. Franz and S. Franz screened more bones from the Furtherland Farms Crocodylus rhombifer Cuvier, 1807 sediments. Specimens Examined. — Only cranial and Prospect (19°16’N, 81°20’W; MM645314). mandibular elements are listed separately —A nearly complete skull with mandibles here. More detailed information on the and a partial postcranial skeleton of a sin- postcranial material is available in the ver- gle Crocodylus rhombifer were found in a tebrate paleontology collection of the Flor- mangrove swamp just north of Prospect. ida Museum of Natural History. The specimen was collected on the surface Chisholm Cow Well: nearly complete and appears to be quite recent, because the skull (UF 80000), associated premaxilla and bones are white and unmineralized. This maxilla (UF 128085), associated frontals (UF skeleton was found about 1980 by a Mrs. 128086), 2 ectopterygoids (UF 128069, Pierce who gave it to Lear Grimmer. Mr. 128087), prefrontal (UF 128070), complete Grimmer subsequently donated the spec- mandible (UF 128065), associated angular imen to the UF vertebrate paleontology and surangular (UF 128066), angular (UF collection. 128088), surangular (UF 128067), articular Age of Fossil Deposits. — Two radiocarbon (UF 128068), 35 isolated teeth (UF 128089), (14C) dates were obtained from samples of 43 assorted postcranial elements (UF mangrove peat from the Crocodile Canal 128071-128084, 128090-128098). Mini- site (Morgan and Woods, 1986). One of the mum number of individuals represented peat samples contained crocodile bones and in sample is 5. the other was collected in direct associa- Connally Cow Well: nearly complete tion with crocodile remains. Both dates skull (original in MRCU; cast-UF 128064). were analyzed by the Smithsonian Insti- Crab Cave: 1 tooth (UF 22739). tution (SI) Radiocarbon Laboratory. The Crocodile Canal: nearly complete skull dates are presented with a ± factor of one (USNM 216197 ), 2 premaxillae (UF 61101- standard deviation and the SI lab numbers 61102), 2 maxillae (UF 61103-61104), 1 in parentheses. The first sample (SI-5068), frontal (UF 61 162), associated jugal and lac- containing a tooth and an osteoderm of rimal (UF 61105), associated jugal and qua- FOSSIL CROCODILES FROM GRAND CAYMAN 157 dratojugal (UF 61106), 2 pterygoids (UF nearly complete skulls along with many 61107-61108), 3 ectopterygoids (UF 61109- isolated cranial elements, mandibles, and 61111), 3 dentaries (UF 61112-61114), 2 an- postcranial bones (Figs. 1-3). The excellent gulars (UF 61115-61116), 4 surangulars (UF preservation of the Grand Cayman fossils 61117-61119, 61163), 7 articulars (UF permits detailed comparisons of these 61120-61126); 69 isolated teeth (UF 61142, skulls with those of the two species of Croc- 61164, 61165), 81 assorted postcranial ele- odylus now found in the West Indies, C. ments (UF 61127-61145, 61166-61171). acutus and C. rhombifer, as well as the Mid- Minimum number of individuals repre- dle American species, C. moreletii. To elim- sented in sample is 6. inate morphological differences related to Furtherland Farms Cow Well: partial ontogenetic factors, only skulls of approx- cranial roof (UF 128128), 2 maxillae (UF imately the same size as the Grand Cayman 128134, 128135), 3 lacrimals (UF 128101, fossils were used for comparisons. Croco- 128136, 128137), squamosal (UF 128138), dylus acutus is a widespread species occur- dentary (UF 128139), 2 splenials (UF 128102, ring in southernmost Florida, throughout 128129), articular (UF 128140), 12 isolated most of the Greater Antilles, and from both teeth (UF 128111, 128141), 80 assorted post- coasts of Mexico south to northern South cranial elements (UF 128102-128110, America. Crocodylus moreletii is restricted to 128109-128127, 128130-128133, 128142- the Gulf and Caribbean drainages of Mid- 128159). Minimum number of individuals dle America from central Tamaulipas Prov- represented in sample is 3. ince in Mexico south to Belize and Gua- Prospect: nearly complete skull, right temala. and left mandibles, humerus, femur, and Varona (1966) compared the skulls of about ten vertebrae, all from a single in- Crocodylus acutus and C. rhombifer, noting a dividual (UF 65800). number of characters that readily separate Modern Distribution. — The Cuban croco- the two species. We compared these same dile, Crocodylus rhombifer, is restricted to features in two skulls of C. moreletii. The Cuba, Isla de Pines, and the Archipielago Grand Cayman fossils closely resemble C. de los Canarreos (Varona, 1966; Schwartz rhombifer. Unless otherwise noted, all char- and Henderson, 1991). Historical evidence acters discussed here for modern Cuban and fossils confirm that C. rhombifer was specimens of C. rhombifer pertain to the once more widely distributed in Cuba (Va- Grand Cayman fossils as well. Crocodylus rona, 1966, 1984). rhombifer skulls have a comparatively Fossil Record. — Varona (1984) reported shorter, broader, and deeper snout than C. fossils of Crocodylus rhombifer from three acutus, which has a narrower and more flat- localities in central Cuba: the springs at tened rostrum. The rostrum of C. rhombifer Ciego Montero, a fissure in the Sierra de is particularly deep just anterior to the or- Jatibonico, and the caves of Cueiba in the bits. C. moreletii is somewhat intermediate Sierra de Remedios. The fossil species C. between these two species in the length of pristinus, described by Leidy (1868) based the snout, but the depth of the rostrum is on a single damaged vertebra from Ciego more like that of C. acutus. The premaxilla Montero, was considered a synonym of C. of the Cuban crocodile also is broader, rhombifer by Varona (1984). Varona (1966) shorter, and deeper than that of C. acutus. described a second extinct species from In C. rhombifer and C. moreletii, the dorsal Cuba, C. antillensis, from a fossil deposit in surface of the premaxilla along the midline Cueva Lamas near Santa Fe on the north- bears a short, blunt process that extends no ern coast of the island just west of Havana. farther posteriorly than the second max- Morgan and Patton (1979) reported a sin- illary tooth. The premaxilla of C. acutus has gle tooth of Crocodylus sp. from Crab Cave a narrow, elongated, triangular-shaped on Grand Cayman. process extending posteriorly to the level Description and Comparisons. — The im- of the third or fourth maxillary tooth. These pressive sample of crocodile fossils now three species also differ in the shape of the available from Grand Cayman includes four premaxillary/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 the snout and the anterior edge of the external level of the first maxillary tooth in C. rhom- narial opening is reduced in C. rhombifer bifer and C. moreleti, while in C. acutus it is and C. moreletii. In C. acutus, the anterior W-shaped and extends posteriorly to the portion of the premaxilla is longer and the third maxillary tooth. Compared to C. acu- narial opening begins farther posteriorly, tus, the distance between the tip of the 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 the region in C. acutus and C. moreletii is only frontals, postorbital, squamosals, and pa- slightly concave and the ridges on the in- rietals, is markedly concave along the mid- ner margin of the orbits are weakly de- line in the region of the dorsal temporal veloped. The combination of a deeper openings (Figs. 1–3). The lateral edges of snout, elevated cranial roof, and more con- the cranial roof are strongly upraised, stricted interorbital region gives C. rhom- forming prominent ridges on the postor- bifer a noticeably larger orbit than C. acutus bital and squamosals. There is a strong or C. moreletii. rounded protuberance on the posterolat- Modern skulls of C. rhombifer have 13 eral corner of the squamosal. Crocodylus (sometimes 12) maxillary teeth. Seven fos- acutus and C. moreletii have a flat cranial sils from Grand Cayman have the complete roof and the squamosal protuberances are maxilla preserved on at least one side, all absent. The region between the orbits, with 13 teeth. All specimens of C. acutus principally the frontals, is deeply concave and C. moreletii examined have 14 maxillary in the Cuban crocodile and the lateral edg- teeth. The third largest tooth in the den- es form a strong raised ridge on the inter- tary (after the 4th and 1st) is the 10th tooth nal margin of the orbits. The interorbital in 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.

Connally Cow Well Chisholm MRCU/CINM Prospect Cow Well UF 128064 Crocodile Canal UF 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 48 Length of maxilla 156 133 128 129 Length of maxillary toothrow 148 127 121 125 1 1 Breadth of premaxilla — 53 53 — 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 22 Breadth of cranial roof (at anterior edge) 76 59 56 57 Breadth of cranial roof (at posterior edge) 104 79 75 75 Breadth of skull (at quadrate- 1 quadratojugal suture) 163 119 — 117 1 Measurements not taken because of damage to the fossils. and C. moreletii. In summary, no characters mm long. The skulls from the Chisholm readily distinguish the Cayman crocodiles Cow Well, Connally Cow Well, and Croc- from Cuban C. rhombifer of similar size. odile Canal sites are smaller, ranging from Measurements. — Although large individ- 247-255 mm. Most of the skulls and post- uals of Crocodylus rhombifer are now rare in cranial elements of C. rhombifer from Grand Cuba due to overhunting, historical evi- Cayman appear to represent juvenile or dence and the fossil record demonstrate subadult individuals (C. Brochu, pers. that this species can reach a very large size. comm.). Gundlach (1880) mentioned a specimen Comparative Material Examined. — All 17.5 feet (5.3 m) long. Adults of this species comparative specimens consisted of mod- now are generally less than 3.5 m. We mea- ern skulls, with the exception of several sured several fossils of C. rhombifer in the fossil skulls from Cuba. The country of or- AMNH from Ciego Montero in Cuba that igin, number of specimens examined, and must have come from enormous individ- the museum collection abbreviation are uals, including a skull 677 mm long and a provided for the comparative material rep- mandible 818 mm in length. Comparisons resenting each of the three species. Croc- with modern crocodilian skulls (Thorb- odylus rhombifer: Cuba (1 AMNH, 1 MCZ, jarnson and McIntosh, 1987) suggest that 1 UF); fossil skulls, Ciego Montero, Cuba these fossils came from animals over 5 m (4 AMNH); C. acutus: Florida (6 UF), Do- in length. minican Republic (1 UF), Haiti (2 UF), Cay- Comparative measurements of the four man Islands, Little Cayman (1 MCZ), Ja- most complete skulls of C. rhombifer from maica (1 AMNH), Mexico (1 MCZ, 1 Grand Cayman are presented in Table 1. USNM); C. moreletii: Mexico (1 UF, 1 The largest skull (Prospect specimen) is 305 USNM). 162 G. S. MORGAN ET AL.

D ISCUSSION notes (1888:101), “Two species of crocodiles have been taken on this island [Little Grant (1940) and Morgan and Patton Cayman] and one on Cayman Brat. I [May- (1979) summarized the historical literature nard] saw but a portion of one specimen. on the occurrence of crocodiles in the Cay- The natives assured me the species were man Islands. Several quotations cited by similar to those found in Cuba. ” In refer- them are repeated here. The earliest known ence to Garman’s records, Barbour (1914: reference to crocodiles in the Cayman Is- 345) stated, “The species referred to are lands was in Walter Bigges’ 1589 narrative doubtless C. rhombifer and C. americanus [=C. on one of Sir Frances Drake’s Caribbean acutus]. Whether they are resident on the voyages. According to Bigges, on the 20th Cayman Group or whether they only reach day of April 1586, Sir Frances Drake’s fleet, the islands occasionally by swimming “. . . fell with two islands called Caimanes, would be well worth ascertaining defi- where we refreshed ourselves with many nitely.” Crocodiles apparently inhabited allagartas and greate turtoises, being very the three Cayman Islands until at least the ugly and fearefull beasts to behold, but late nineteenth century. Individual croc- were made good meate to eate . . .“ Bigges’ odiles have been reported sporadically term allagartas (also alagarto) is an earlier within the last 50 years, including a spec- English spelling of alligator and is derived imen of Crocodylus acutus captured along from the Spanish el lagarto. In the early the southern coast of Little Cayman in 1939 English historical literature from the West (Grant, 1940) and an unknown species of Indies, alligator or its prior equivalent was crocodile captured on Cayman Brat in the often used as a general term for crocodil- 1950’s (Seidel and Franz, in press). ians. Bigges’ references to two islands in- A radiocarbon date of 860 yBP from the dicates that Drake visited Little Cayman Crocodile Canal Site establishes the pres- and Cayman Brat. ence of Crocodylus rhombifer on Grand Cay- The next reference to crocodiles in the man in pre-Columbian times. The second Cayman Islands was in 1642 or 1643 by a radiocarbon date of 375 yBP from the Croc- Captain William Jackson (from Grant 1940: odile Canal Site and the presence of Rattus 3) who stated, “. . . ye island of Chimanos rattus in association with C. rhombifer in the [apparently Grand Cayman] . . . this place Furtherland Farms Cow Well, clearly in- is low land and all rockye, and there bee dicate that Cuban crocodiles inhabited other two Islands of ye same name and Grand Cayman when the Cayman Islands Quallitie [Little Cayman and Cayman Brat], were discovered by Columbus in 1503. being by ye Spanyards called Chimanos, The discovery of fossil crocodile bones from ye multitude of Alligators here found from Grand Cayman may have some bear- which are Serpents, if not resembling ye ing on how the Cayman Islands were Crocodiles of Egypt.” In his history of Ja- named. These islands are called Islas Cai- maica, Edward Long (1774:875) noted that, man in Spanish. The Amerindian word cai- “. . . the crocodile . . . is found at Grand man has been incorporated into the Span- Caymanas . . . .“ ish language as a general term for all According to Grant (1940), the first her- crocodilians, and is the local Cuban name petological collection from the Cayman Is- for Crocodylus acutus (DeSola, 1930; Varona, lands was made on Grand Cayman in 1886 1966). The prior abundance of Crocodylus by W. B. Richardson and reported by Gar- rhombifer on Grand Cayman strongly sug- man (1887). In discussing the occurrence gests that the Cayman Islands were named of crocodiles on Grand Cayman, Garman for their formerly resident crocodiles. stated (1887:276), “Mr. Richardson states The occurrence on Grand Cayman of that the natives reported a crocodile in the Crocodylus rhombifer rather than the more swamps. ” The following year Garman widespread C. acutus is puzzling, particu- (1888) reported on a collection made by C. larly considering that C. acutus prefers J. Maynard on Little Cayman and Cayman coastal marine and brackish-water habi- Brat. Garman quoted from Maynard’s field tats, while C. rhombifer inhabits freshwater FOSSIL CROCODILES FROM GRAND CAYMAN 163 marshes and swamps in Cuba (DeSola, 1930; McDonald, Paul Moler, and Blair Smith. Varona, 1966). Large portions of Grand Rolin Chisholm generously donated a sam- Cayman are below 5 m in elevation and ple of crocodile fossils, including a com- are characterized by mangrove swamps, plete skull and mandibles, from Grand brackish lagoons, and other habitats fa- Cayman to the Florida Museum of Natural vored by C. acutus. The occurrence of C. History and Edward Materne donated a rhombifer fossils in mangrove swamps in complete fossil crocodile skull and other two localities on Grand Cayman suggests bones to the National Museum of Natural that this species may have occupied a wid- History, Smithsonian Institution. In 1980 er variety of habitats than it does presently. the late Ira Thompson kindly allowed us Furthermore, to reach Grand Cayman from to examine his extensive collection of croc- southern Cuba, individuals of C. rhombifer odile fossils from Grand Cayman, which is would have to cross 250 km of open ocean, now housed in the Cayman Islands Na- a difficult feat for an animal supposedly tional Museum. Jose Ottenwalder and John restricted to freshwater. Thorbjarnarson provided information on There is little doubt that Crocodylus rhom- extant Caribbean crocodiles. Kenneth bifer was a breeding resident on Grand Cay- Dodd, Wayne King, and Perran Ross made man, based on the large sample sizes of helpful comments on an earlier draft of the fossils in the Chisholm Cow Well, Croco- manuscript. GSM and RF extend their dile Canal, and Furtherland Farms Cow thanks to the government of the Cayman Well sites, as well as the presence of nu- Islands, as well as J. E. Davies and the merous bones belonging to hatchlings or MRCU, for funding they received to con- very small individuals. The evidence for duct a paleontological and herpetological C. rhombifer on Little Cayman and Cayman survey of the Cayman Islands in January Brat is much less convincing. Except for 1986. Dr. Davies and his staff at the Mos- one museum specimen of C. acutus from quito Research and Control Unit and Na- Little Cayman, the occurrence of croco- tional Resources Study in George Town, diles on these two islands is based on in- Grand Cayman have assisted us in all conclusive sight records. phases of our field research in the Cayman The disappearance of crocodiles and Islands. This is University of Florida Con- many other species of vertebrates from the tribution to Paleontology Number 406. Cayman Islands during the last 500 years probably resulted from a combination of LITERATURE CITED human-caused habitat destruction and pre- Barbour, T. 1914. A contribution to the zoogeogra- dation (Morgan and Woods, 1986; Morgan, phy of the West Indies, with especial reference to in press). Among the many extinct and ex- amphibians and reptiles. Mem. Mus. Comp. Zool. tirpated vertebrates from the Cayman Is- 44(2):209-359. DeSola, C. R. 1930. The Cuban crocodile, an account lands, only the crocodile is mentioned in of the species Crocodylus rhombifer Cuvier, with the historical literature. Numerous refer- notes on its life history. Copeia 1930(3):81-83. ences from the sixteenth century onward Garman, S. 1887. On the reptiles and batrachians of confirm that crocodiles inhabited the Cay- Grand Cayman. Proc. Amer. Phil. Soc. 24:273-277. ———. 1888. Reptiles and batrachians from the Cay- man Islands until at least the late nine- mans and from the Bahamas. Bull. Essex Inst. 20: teenth century. 101-113. Grant, C. 1940. The herpetology of the Cayman Is- Acknowledgments. — We are especially lands. Bull. Inst. Jamaica, Sci. Ser. 2:1-65. grateful to the many people who have as- Gundlach, J. 1880. Contribucion a la erpetologia de Cuba. Imp. G. Montiel, La Habana. 99 pp. sisted us in collecting or obtaining fossil Leidy, J. 1868. Notice of some vertebrate remains crocodile specimens from Grand Cayman, from the West Indian islands. Proc. Acad. Nat. Sci., including Jack Andresen, Jacqueline Bel- Philadelphia. pp. 178-180. wood, Nina Thanz Borremans, Rolin Chis- Long, E. 1774. The history of Jamaica. London (3 vols.). holm, J. E. Davies, Shelley Franz, Lear Morgan, G. S. In press. Late Quaternary fossil ver- Grimmer, Reginald Koster, Margaret Lang- tebrates from the Cayman Islands. In J. E. Davies worthy, Edward and Robert Materne, Greg and M. Brunt (eds.), Biogeography and ecology of 164 G. S. MORGAN ET AL.

the Cayman Islands. Monographiae Biologicae, and reptiles of the Cayman Islands. In J. E. Davies Kluwer Academic Publishers, Dordrecht, Neth- and M. Brunt (eds.), Biogeography and ecology of erlands. the Cayman Islands. Monographiae Biological, ———, and T. H. Patton. 1979. On the occurrence Kluwer Academic Publishers, Dordrecht, Neth- of Crocodylus (Reptilia, Crocodilidae) in the Cay- erlands. man Islands, British West Indies. J. Herp. 13(3): Thorbjarnarson, J. B., and P. E. McIntosh. 1987. Notes 289-292. on a large Melanosuchus niger skull from Bolivia. ———, and C. A. Woods. 1986. Extinction and the Herp. Rev. 18(3):49, 52. zoogeography of West Indian land mammals. Biol. Varona, L. S. 1966. Notas sobre los crocodilidos de J. Linnean Soc. 28:167-203. Cuba y descripcion de una nueva especie del Pleis- Schwartz, A., and R. W. Henderson. 1991. Amphib- toceno. Poeyana, ser. A, No. 16:1-34. ians and reptiles of the West Indies. University of ———. 1984. Los crocodilos fosiles de Cuba (Rep- Florida Press, Gainesville, Florida. 720 pp. tilia: Crocodylidae). Carib. J. Sci. 20(1-2):13-18. Seidel, M. E., and R. Franz. In press. The amphibians