Systematics of Diplodactylus (Squamata: Diplodactylidae) from the south-western Australian biodiversity hotspot: redefinition of D. polyophthalmus and the description of two new species

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – The Australian gecko genus Diplodactylus is characterised by morphologically similar but genetically divergent lineages and taxa. Recent molecular analysis indicated the presence of an undescribed Diplodactylus from the Geraldton Sandplain on the western coast of Australia, and a relatively deep divergence between populations of D. polyophthalmus on the Swan Coastal Plain (around Perth) and the Darling Range (inland and south of Perth). Here we present a more detailed investigation of genetic and morphological variation among these forms. The two genetically divergent populations of D. polyophthalmus do not differ appreciably in morphology but differ in dorsal colouration and ecology. Since the lectotype of D. polyophthalmus was collected from ‘Champion Bay’ (near Geraldton) and is in agreement with specimens collected from there, we redescribe this species and restrict its range to the coastal sandplain from Perth to Eneabba. The Darling Range population, regarded as typical D. polyophthalmus since Storr’s 1979 ressurrection, differs in that it is consistently darker with a rusty-brown colouration and occurs on hard surfaces such as laterite. As the lectotype of D. polyophthalmus refers to the coastal sandplain form, we describe the Darling Range form as a new species, D. lateroides sp. nov. Genetic and morphological evidence also confi rmed the existance of a highly divergent lineage that forms a polytomy with D. capensis and D. granariensis. This lineage, here described as Diplodactylus nebulosus sp. nov., has a restricted range, occurring from near Geraldton in the north to Mt Lesueur ~200 km to the south. Like its close genetic relatives, the new species has enlarged labial and supranasal scales, making it relatively easy to distinguish from the regionally sympatric D. ornatus and D. polyophthalmus. The conservation status of some species of Diplodactylus in south-western Australia need to be carefully considered, especially southern populations of the redefined D. polyophthalmus.