Evolution and biogeography of West Indian Sphaerodactylus (Sauria: Gekkonidae): a molecular approach

Abstract

This study investigated the phylogenetic relationships and biogeographic history of West Indian geckos belonging to the genus Sphaerodactylus through an analysis of protein variation. Two techniques were used: sequential starch gel electrophoresis of 15 slow‐evolving loci and microcomplement fixation of albumin. The relationships obtained were used to revise the classification of this genus. Two major groups (subsections) occur in the West Indies. The sputator subsection, centred in the Greater Antilles, is composed of three series: cinereus, sputator and argus. The fantasticus subsection, restricted to the Lesser Antilles, includes only the fantasticus series.Three antibodies (argus, asterulus and copei) were used to investigate albumin evolution and estimate times of divergence within Sphaerodactylus. Using the albumin clock calibration derived from other groups, the West Indian Sphaerodactylus had diverged from other sphaerodactylines by approximately 27 million years before present (mybp). Therefore, fragmentation of the Proto‐Antilles (60 mybp) apparently did not play a role in the group's evolution. The present distribution of West Indian Sphaerodactylus resulted from dispersal. Hispaniola probably was the centre of Sphaerodactylus diversity and the source of colonists for other islands. Certain features of Sphaerodactylus ecology and physiology make them likely candidates for dispersal. In contrast to the West Indian species of Anolis and Eleutherodactylus, few exampies of morphological convergence are found in Sphaerodactylus. Allopatric speciation, perhaps due to climatic changes in the Pliocene and Pleistocene, is suggested as the primary mechanism of species formation in West Indian Sphaerodactylus.