Morphological variation and the definition of species in the snake genus Tropidophis (Serpentes, Tropidophiidae)

Abstract

SYNOPSIS. Historically, the definition of species in the Neotropical snake genus Tropidophis has been difficult because of intraspecific variation in scalation and a paucity of specimens of most taxa. There were 13 species recognized at the time of t he last review in 1960, but additional species have since been discovered and a taxonomic review and update is needed. Data on morphological variation are presented here and used to clarify the status of the described taxa. Because many taxa are allopatr ic with their closest relatives, it is necessary to make decisions as to their status as species or subspecies. As a gauge of spec ies status in the genus, character divergence in ten pairs of closely related sympatric species was examined. Typically, such species are differentiated by two non-overlapping colour pattern differences, often in combination with a diagnostic (non-overlapping) or overlapping difference in scalation. Using this criterion, seven taxa previously considered as subspecies are here elevated to species status, whereas seven other taxa are retained as subspecies, although in some cases they are allocated to different spe cies. As a result, the genus Tropidophis is considered here to comprise 29 species, 26 of which are West Indian and 15 of those are restricted to Cuba.