SNAKE OF THE GENUS TROP1DOPHIS 



89 



single genetic and morphological group (jamaicensis group), and 

 are distinguished morphologically from the Cuban species at the 

 species level, although they are closest to species of the pardalis 

 group. The question then remains as to whether they should be 

 treated as a single species (T jamaicensis) or three separate species: 

 T. jamaicensis, T. stejnegeri, and T. stullae. However, using the 

 morphological criterion for species status, I recommend the latter. 

 Each of these three taxa can be diagnosed based on scalation, body 

 proportions, and colour pattern, and they are as different from each 

 other as sympatric species in Cuba. In body size, T. stejnegeri (529 

 mm S VL) is considerably larger than T. stullae (260 mm S VL), with 

 T. jamaicensis (338 mm SVL) being intermediate in size. Ventral 

 counts of T. stejnegeri do not overlap with those of T. stullae, and 

 counts of T. jamaicensis are nearly completely non-overlapping 

 with the other two taxa. Tropidophis stejnegeri has keeled scales and 

 occipital spots whereas the other two taxa are smooth scaled and 

 lack occipital spots. Additionally, dorsal ground colours differ, 

 being yellowish-grey (T. stejnegeri), chocolate brown (T. 

 jamaicensis) and pale tan (T stullae). A middorsal stripe is present 

 in T. stejnegeri and T. stullae but absent in T. jamaicensis. The head 

 of T. stejnegeri is pointed but that of T. stullae is distinctly squared- 

 shaped. 



The Bahamas Bank 



Six taxa are currently recognized from the Bahamas Bank: 

 Tropidophis canus androsi Stull (Andros Island), T. c. barbouri 

 Bailey (central Bahamas, from Eleuthera to Ragged Island), T. c. 

 canus Cope (Great Inagua), T. c. curtus Garman (New Providence, 

 Bimini Islands, and Cay Sal Bank), T. g. greenwayi Barbour and 

 Shreve (Ambergris Cay), and T. g. lanthanus Schwartz (Caicos 

 Islands). Schwartz and Marsh (1960) considered all except the last 

 two to be subspecies of a single species (T. canus) and that arrange- 

 ment has since been followed. However, it is worth reviewing 

 morphological variation in T. canus in the context of our current 

 understanding of species definitions in the genus. Recent evidence 

 from DNA sequences has shown that T greenwayi is most closely 

 related to T. haetianus (Hispaniola) and unrelated to the complex 

 currently considered under T. canus. 



Among the four subspecies of T. canus, T. c. canus stands out both 

 morphologically and geographically. It is isolated in the south, being 

 separated from the northern taxa by islands apparently lacking 

 Tropidophis: Crooked, Acklins, Mayaguana, and Little Inagua. It 

 has a higher number of ventrals (170-183). One specimen (1%) of 

 the northern group has 173 ventrals; all others have fewer than 168 

 ventrals. Anterior and midbody scale rows in T c. canus typically 

 are 21-23 whereas they are typically 23-25 in the northern taxa, 

 although there is some overlap. The tails of T. c. canus are distinctly 

 shorter, averaging 11% (9.4-12.1), compared with 13% (11.0-15.2) 

 in the northern taxa. Rows of body spots number 6-8 in T. c. canus 

 whereas they are typically 10 or more in the northern taxa; overlap 

 consists of nine specimens (10%) of northern taxa with eight rows 

 and two (2%) with nine rows, and one (5%) T. c. canus with nine 

 rows. This degree of difference is the same or greater than that seen 

 between sympatric species of Tropidophis in Cuba, and therefore the 

 northern taxa should be removed from T canus. 



The status of the three northern Bahaman taxa is problematic at 

 this time. Clearly there is geographic variation among these forms. 

 For example, androsi tends to have a higher number of ventral scales 

 than the other two taxa, although there is considerable overlap with 

 barbouri and some with curtus. Within one taxon (curtus), snakes 

 from Bimini are distinctly larger than those from New Providence. 

 Both Bailey (1937) and Schwartz and Marsh (1960) noted very little 



difference, overall, between barbouri and androsi. When consider- 

 ing the 'species boundary' characters noted above, there is insufficient 

 justification at present to recognize these taxa as distinct species. 

 Additional specimens and genetic analyses will be necessary to 

 better resolve geographic variation in northern Bahaman Tropidophis. 

 Until then, I suggest here that androsi and barbouri be recognized as 

 subspecies of T curtus: T. curtus androsi (new combination) and T. 

 curtus barbouri (new combination). 



Tropidophis greenwayi lanthanus is a subspecies found in the 

 Caicos Islands and is distinguished by coloration difference from the 

 nominate subspecies on nearby Ambergris Cay (Schwartz, 1963). 

 However, the difference concerns 'interspace stippling' and not 

 actual numbers of spots or spot rows. There are no diagnostic scale 

 count differences, and the presence of two postoculars in the two 

 known specimens of T g. greenwayi is not remarkable because half 

 of the specimens of T. g. lanthanus also have two postoculars, at 

 least on one side of the head. More material of T. g. greenwayi is 

 needed, in addition to genetic analyses, before the species status of 

 T g. lanthanus can be accurately assessed. I suggest that the latter 

 taxon continue to be recognized as a subspecies. 



Thus, Tropidophis of the Bahamas Bank are placed here in three 

 species: T. greenwayi (Turks and Caicos), T. canus (Great Inagua), 

 and T. curtus (northern and central Bahamas). The question as to 

 whether some Bahaman species also occur in Cuba has been raised 

 in the past, primarily because of two old specimens (Schwartz & 

 Marsh, 1960). The first is the type of T. curtus, purportedly from 

 'Cuba' (Garman, 1887). However, morphologically it agrees with 

 snakes from New Providence, Bahamas, and the specimen number 

 (MCZ 61 14) is close to other numbers in that collection from New 

 Providence. Also, the origin of the specimen was investigated and 

 found to be 'without definite history' (Stull, 1928). Thus, I agree 

 with Stull in considering this specimen to be from New Providence. 

 The other specimen is AMNH 2946 from 'Nuevitas, Cuba' (no other 

 information). As noted by Schwartz and Marsh (1960) it agrees in 

 morphology with snakes here considered as T curtus. Although they 

 considered the provenance of the specimen to be correct, partly 

 because of the confusion surrounding the holotype, I raise the 

 question here that it also may be an error. The specimen number is 

 close to several T. curtus from Andros Island (AMNH 2925-2927) 

 apparently cataloged at about the same time and its scale counts fall 

 within the range of counts of snakes from that island. Thus I consider 

 the range of T curtus to be restricted to the Bahamas. 



The Cayman Islands 



Currently there are three subspecies of T. caymanensis recognized 

 from the Cayman Islands (Thomas, 1963) and they differ in scale 

 row counts, ventral counts, and colour pattern. Each is endemic to a 

 single island, and there is no evidence of intergradation. At the time 

 they were last reviewed (Thomas, 1963), a more conservative 

 definition of species boundaries in the genus prevailed. Although no 

 new material has been examined here, the level of differences seen 

 among these taxa would suggest that they are distinct species. 

 Tropidophis caymanensis (Grand Cayman) is distinguished from T 

 parkeri (Little Cayman) by its lower anterior and midbody scale 

 rows (23-25 versus 25-27), lower number of ventrals (183-200 

 versus 199-212), and a larger, darker cephalic pattern. Tropidophis 

 caymanensis is distinguished from T schwartzi (Cayman Brae) by 

 its larger body size (maximum SVL = 470 mm versus 385 mm), 

 lower anterior scale rows (23 versus 25), lower, albeit overlapping, 

 number of ventrals (183-200, x = 192, versus 191-205, x = 198), 

 fewer tail spots (4-8, mode = 6 versus 5-9, mode = 8) and a larger, 

 darker, cephalic pattern. Tropidophis parkeri is distinguished from 



