Genetic elucidation of cryptic and ancient diversity in a group of Australian diplodactyline geckos: The Diplodactylus vittatus complex

We examine species boundaries and phylogenetic relationships within the Australian diplodactyline geckos currently assigned to Diplodactylus granariensis and Diplodactylus vittatus using data from multiple allozyme loci, the mitochondrial ND2 gene and published karyotypic studies. These analyses uncover at least six morphologically cryptic but genetically distinctive species. The taxa identified correspond poorly with the existing taxonomy and represent a paraphyletic assemblage with respect to a number of other Diplodactylus species included in analyses. Molecular dating indicates that the species identified evolved considerably before the Pleistocene, and that the basal node of the D. vittatus species group (as redefined here) is of comparable age to entire radiations of other Australian squamate families. The antiquity of this one small group within the diplodactyline geckos suggests that further study of patterns of diversification in the diplodactylines will provide both a valuable insight into long-term patterns of environmental change in the Australian continent and a useful contrast for analysis of patterns of radiation in other Australian lizard groups.