Ancient phylogeographic divergence in southeastern Australia among populations of the widespread common froglet, Crinia signifera

Abstract

Geographic patterns of species diversity in southeast Australia have been attributed to changes in Pleistocene climate, but related phylogeographic patterns and processes are relatively understudied. 12S and 16S mitochondrial DNA sequences in Crinia signifera populations were used to infer historical patterns and processes in southeast Australia. Phylogenetic analysis identified three geographically restricted ancient lineages and several geographically restricted sub-clades. Present-day features that may prevent gene flow are absent between these geographic regions. Divergence among the three lineages corresponds to a late Miocene origin, approximately 9 million years ago (mya). The geographic breaks among the lineages are consistent with Miocene-Pliocene uplift in the Great Dividing Range and elevated sea levels in East Gippsland. Divergence among sub-clades in Victoria and South Australia is estimated to be within the early Pliocene, whereas sub-clades in New South Wales are estimated to have diverged near the Plio-Pleistocene boundary, approximately 2 mya. Geographic limits of sub-clades are consistent with geographic variation in advertisement calls, but are inconsistent with phylogeographic limits previously identified in other southeastern species.