86 















S.B. HEDGES 



Table 3 Variation 



in scalation of snakes of the genus 



Tropidophis. (Numbers 



and character states in 



brackets represent rare or infrequent occurrences; Y = 



yes, N = no; other notation as in Table 2. 























Dorsal scale rows 





Parietal 



Keeled 



Species 



Ventral s 



Caudals 



Anterior 



Midbody 



Posterior 



contact 



dorsals 



T. battersbyi 



200 



41 



21 



23 



17 



N 



N 



T. bucculentus 



183-186 



28-32 



24-25 



25-27 



17-19 



N 



Y 



T. canus 



170-183 



29-35 



21 [20.22,23] 



23[22] 



16-21 



N/Y 



Y[N] 



T. caymanensis 



1 83-200 



33-38 



23-27 



23[25] 



17[19] 



N 



N/Y 



T. celiae 



203 



30 



25 



27 



19 



Y 



N 



T. curtits 



146-173 



22-37 



19-27 



23-25 



17-22 



N[Y] 



Y[N] 



T. feicki 



217-235 



34^11 



23-25[19,21] 



23-25 



17-19 



N/Y 



N 



T. fuscus 



160-185 



30-36 



21-24 



23 



15-19 



N 



Y 



T. galacelidus 



177-186 



29-35 



25-27 



25-27 



19-20 



N 



Y 



T. greenwayi 



155-165 



26-30 



23-25 



25-27 



17-19 



Y 



N 



T. haetianus 



170-194 



27-39 



23-27 



25-27[23,29] 



17-19[21] 



Y[N] 



N 



T. hardyi 



153-172 



31-48 



20-24 



23-25 



18-20 



N/Y 



N/Y 



T. hendersoni 



190 



33 



23 



25 



19 



N 



Y 



T. jamaicensis 



167-181 



28-36 



23-27 



25-29 



15-23 



N/Y 



N 



T. maculatus 



189-208 



28-40 



22-25 



25[23] 



17-21 



N/Y 



N/Y 



T. melanurus 



188-217 



31^44 



24-27 [19] 



27-29 

 [24,25,26,30] 



17-21 



[16,22,23,24] 



N 



Y 



T. morenoi 



198-199 



42-44 



23 



23 



17 



N 



N 



T. nigriventris 



144-150 



25-26 



23-25 



23-25 



18-22 



N 



N 



T. pardalis 



140-157 



23-34 



21,23 

 [19,22,24,25] 



23,25 

 [21,22,24] 



1 7-2 1 [ 1 6] 



N/Y 



N[Y] 



T. parked 



199-212 



33^41 



25[23,24] 



27[25,26] 



17[18.19] 



N 



Y 



T. paucisquamis 



170-178 



37-40 



21 



21 



17 



Y 



N 



T. pilsbryi 



160-169 



26-31 



22-25 



23-25 



17-21 



N 



N/Y 



T. schwartzi 



191-205 



31-39 



25 



25[26] 



17[15] 



N 



Y 



T. semicinctus 



201-223 



33-41 



21.23[22,24,25] 



25 [2 1-24] 



17-20 



N/Y 



N 



T. spiritus 



183-200 



35-39 



21-23 



23 



17 



N 



N 



T. stejnegeri 



181-190 



30-38 



25-27[23] 



25,27[26] 



17-19 



N/Y 



Y 



T. stullae 



166-170 



31-34 



25 



25 



16-19 



N 



N 



T. taczanowskyi 



149-160 



25-27 



23-25 



23 



19-21 



Y 



Y 



T. wrighti 



192-215 



36-45 



21-23 



21-23 



17[16.18,19] 



N 



N 



heads and fewer spots than the pale snakes (thus, body colour would 

 be covarying with head size and spot number). In the case of 

 allopatric populations, it is typically assumed that character differ- 

 ences similar to or greater than observed between sympatric species 

 indicate that the two forms are different species. Thus, the 'yard- 

 stick' used for assessing allopatric populations is character divergence 

 between closely related, sympatric species. This is the principle that 

 I use here in assessing species status within Tropidophis. It is a 

 practical species concept but is based on the observation that species 

 are reproductively isolated from each other, as noted by Darwin 

 ( 1 859) and later articulated by Mayr ( 1 942) as the biological species 

 concept. 



The reason that a particular degree of differentiation is necessary, 

 rather than a minimal diagnostic difference, concerns the 'reality' of 

 species in evolution. Almost all species are fragmented (structured) 

 to some degree, and many populations can be diagnosed by one or a 

 few nucleotide differences or minor morphological differences. 

 However, through time, such populations frequently combine and 

 separate again as part of the reticulate nature of gene flow and 

 evolution within species. It is only those populations that have 

 differentiated sufficiently, genetically and/or morphologically, and 

 presumably reflecting a length of time, that evolve reproductive 

 isolation from other populations. Thus, to assign species status to 

 diagnosable, but ephemeral, populations during one slice of time is 

 arbitrary from an evolutionary standpoint. Although Frost and Hillis 

 (1990) recommended abandoning the use of quantitative criteria 

 (molecular and morphological) for discerning species status of 

 allopatric populations, they did not propose anything to replace that 

 procedure and thus few have heeded their recommendation. 



Sympatric species of Tropidophis occur only in Cuba. In western 

 Cuba, the following six species have been found in the general 

 region of Canasf, Habana Province: T. celiae, T. feicki, T. maculatus. 

 T. melanurus, T. pardalis, and T. semicinctis. In central Cuba, the 

 following six species have been found in the vicinity of the Trinidad 

 mountains: T. galacelidus, T hardyi, T melanurus, T. pardalis, T. 

 semicinctis, and T spiritus. In eastern Cuba, the following four 

 species are known from the region of Baracoa, Guantanamo Prov- 

 ince: T. fuscus, T. melanurus, T pilsbryi, and T. wrighti. To identify 

 the level of character divergence associated with species differentia- 

 tion in Tropidophis, I now focus on four clusters of sympatric 

 species, each of which are members of the same species group: ( 1 ) 

 feicki/maculatus/semicinctis,(2) celiae/melanurus, (3) pardalis/ 

 galacelidus/hardyi, and (4) fuscus/wrighti/pilsbryi. 



In cluster ( 1 ), T maculatus and T. semicinctis are closest relatives 

 according to DNA sequence evidence (S. B. Hedges, S. C. Duncan, 

 A. K. Peppemey, in preparation) and are distinguished primarily by 

 colour pattern: the number of body spots (no overlap) and number of 

 spot rows (no overlap). All scale counts in those two species overlap, 

 although T. semicinctis tends to have a higher number of ventrals. In 

 the case of T. feicki and T. maculatus, there are non-overlapping 

 differences in ventral counts, body spots, and spot rows. Consider- 

 ing T. feicki and T semicinctis, the ground colour and spot rows are 

 non-overlapping, and the ventral counts are different but overlap 

 slightly. 



In cluster (2), T. celiae and T. melanurus, which are close relatives 

 according to DNA sequence evidence, completely overlap in all 

 scale counts, although parietal contact might be considered diagnos- 

 tic if there were more than one specimen of T. celiae. Otherwise. 



