Historical biogeography of rhacophorid frogs of Japan and the Ryukyu Archipelago inferred from a phylogenetic perspective

Abstract

Samples of rhacophorid fauna were examined from five hypothesized areas of endemism which compose Japan, the Ryukyu Archipelago, and Taiwan, and phylogenetically related or geographically proximate taxa from the Asian continent. From these specimens, phylogenetic hypotheses have been constructed using 355 characters derived from an approximately 1100 bp 12S and 16S ribosomal mtDNA sequence for two distinct lineages (Bueraeria and Rhacophorus) which have representatives inhabiting these areas of endemism. The two resulting phylogenies have been used: (1) to test whether the present distributional patterns of these frogs are the result of past vicariance events, and (2) to present an hypothesis of their historical biogeography. For example, both phylogenies indicate that some species from Taiwan are more closely related to species from Japan proper than to other species in the Ryukyu Archipelago, indicating a relationship that possibly preceded the formation and colonization of the Ryukyu Archipelago. This hypothesis has been analyzed along with the known geology of Japan, Taiwan, and the Ryukyu Archipelago to yield a general biogeographic hypothesis for this region which can be used to evaluate distributional patterns of other fauna and flora in Japan and Asia.