Phylogeography of the Australian freshwater turtle Chelodina expansa reveals complex relationships among inland and coastal bioregions

We examined range-wide mitochondrial phylogeographic structure in the riverine freshwater turtle Chelodina expansa to determine if this species exhibits deep genetic divergence between coastal and inland hydrological provinces as seen in co-distributed freshwater taxa. We sequenced two mitochondrial loci, genealogical relationships were assessed using a network approach, and relationships among biogeographic regions were tested using analyses of molecular variance. Population history was evaluated using neutrality tests, indices of demographic expansion, and mismatch analyses. Twenty one haplotypes were recovered across two mitochondrial haplogroups separated by ca 4% nucleotide divergence. The haplogroups have discrete geographic boundaries but only partially support a hypothesis of deep divergence between coastal and inland bioregions. The first haplogroup comprises populations from the inland Murray-Darling Basin and from coastal catchments south of the Mary River in southeast Queens...