The origin of West Indian amphibians and reptiles

Abstract

The known West Indian herpetofauna is comprised of 175 species of amphibians (99% endemic) and 457 species of reptiles (93% endemic). Informaation on distributions, relationships, and times of origin, with emphasis on estimates of divergence time from albumin immunological data, are analyzed in an attempt to understand the origin of the herpetofauna. Seventy-seven independent lineages of West Indian amphibians and reptiles are identified and nearly all (95%) originated in the New World. Of those lineages for which a source area within the New World can be determined, most (79%) show a South American origin, with smaller contributions from Central America (15%) and North America (6%). One very old and diverse lineage, frogs of the genus Eleutherodactylus, originated by vicariance or dispersal in the late Cretaceous (70 mya). With one possible exception (the xantusiid lizard Cricosaura typica), all other lineages appear to have arrived by dispersal during the Cenozoic, and all but nine lineages in the last half of the Cenozoic (30-0 mya). Most West Indian lineages with multiple endemic species originated in the mid-Tertiary, whereas most lineages with a single endemic species arose in the late Tertiary. Quaternary dispersal is postulated to explain the origin of West Indian populations of mainland species.