Geographical variation in the morphology of four snake species from the Lesser Sunda Islands, eastern Indonesia

Abstract

The morphology of three colubrid snakes, Elaphe subradiata, Psammodynastes pulverulentus, Lycodon aulicus capucinus, and the viper Trimeresurus albolabris, were examined from populations throughout the Lesser Sunda islands using canonical variate analysis. The Lesser Sundas form the western part of two extensive island chains, the Banda Arcs, that lie between the large islands on the Sunda (Asian) and Sahul (Australian) continental shelves. The snakes of the Lesser Sunda islands show considerable intraspecific variation in morphology. Populations of Trimeresurus albolabrisfrom Wetar and Psammodynastes pulverulentusfrom Alor show the greatest morphological separation from conspecifics. The most pronounced morphological differentiation in multidimensional space occurs between populations on islands that remained separated throughout the Pleistocene, when sea levels were about 120 m lower than present. Consensus tree evaluation of Mahalanobis distance for populations of these four species and Dendrelaphis pictuson the islands of Lombok, Sumba, Flores, Lembata and Alor, supports the finding that populations from islands that remained isolated throughout the Pleistocene by sea barriers show the greatest morphological divergence.