Molecular phylogenetics of the arboreal Australian gecko genus Oedura Gray 1842 (Gekkota: Diplodactylidae): another plesiomorphic grade?

Abstract

The family Diplodactylidae is the most ecologically diverse and geographically widespread radiation of geckos within Australasia. Herein we present a first comprehensive phylogenetic analysis of relationships of diplodactylid geckos currently assigned to the genus Oedura, a group of relatively generalised arboreal Australian geckos. Maximum Likelihood, bayesian and Maximum Parsimony analyses of a combination of over two and a half kilobases of nuclear (PDC, Rag-1) and mitochondrial (ND2, ND4, tRNA) sequence data all identified four distinctive lineages within Oedura s.l. Based on their deep divergences and a suite of diagnostic morphological characters we recognise each of these four lineages as genera, two of which are monotypic and newly described herein. Our molecular data also suggest that Oedura s.l. is not monophyletic, but is instead a plesiomorphic grade restricted to islands of rocky or forested habitat around coastal and central Australia. In contrast, combined analysis of all data suggests the Australian arid zone is dominated by a single comparatively derived and relatively species rich clade including most other genera of Australian Diplodactylidae. Additional data are required to properly resolve basal divergence events within the Diplodactylidae, however the emerging pattern of relationships and divergence is consistent with the hypothesis that monsoonal and temperate lineages are ancestral to the arid zone fauna, but also indicate that arid zone lineages and radiations are relatively old, and potentially date back to the mid Miocene or earlier.