Phylogenetic relationships of the Rhacophorus everetti‐group and implications for the evolution of reproductive modes in Philautus (Amphibia: Anura: Rhacophoridae)

Abstract

Hertwig, S., Das, I., Schweizer, M., Brown, R., & Haas, A. (2011). Phylogenetic relationships of the Rhacophorus everetti‐group and implications for the evolution of reproductive modes in Philautus (Amphibia: Anura: Rhacophoridae). —Zoologica Scripta, 41, 29–46.This study presents the first phylogenetic analysis of the enigmatic Rhacophorus everetti species group and the first description of its unique tadpole. A total sample of 95 12S and 16S mitochondrial rDNA sequences were compiled including new sequence data from 28 rhacophorid species. Based on 1332 and 1407 bp, respectively, and on the gap coding method applied, a new hypothesis about the phylogeny of rhacophorid tree frogs from Sundaland was obtained. While Rhacophorus was uncovered as a polyphyletic assemblage, the monophyly of the Bush Frogs of the genus Philautus, including the Rhacophorus everetti‐group, is robustly supported. We, therefore, transfer the everetti‐group to the genus Philautus. As a second step, we recognise Philautus macroscelis (comb. nov.) from Borneo and P. everetti (comb. nov.) from Palawan as distinct allopatric species. Molecular and morphological evidence clearly indicates that each is a distinct lineage with a unique ancestry and discrete evolutionary fate. Moreover, close phylogenetic relationships of several Philautus species from Borneo to taxa from outside Borneo were recovered; P. everetti and P. macroscelis being the only one example. These findings indicate a complex biogeographical history of Sundaland Bush Frogs, which can only be explained by repeated dispersal and vicariance events between the Asian mainland and the Sunda islands. Finally, a single tadpole discovered on Gunung Kinabalu was matched genetically to P. macroscelis. Features of its peculiar external morphology suggest that this larva is endotrophic and possibly nidicolous. A comparable reproductive biology was formerly unknown in rhacophorid tree frogs. The presence of a free‐swimming tadpole in Philautus challenges the notion that terrestrial direct development represents an apomorphic character unambiguously shared by all members of this genus. The implications for the evolution of reproductive modes in Bush Frogs are discussed in a phylogenetic context.