Phylogeography of the Hong Kong Whipping Frog (Polypedates megacephalus) throughout Hainan Island, China

Abstract

The Hong Kong Whipping Frog (Polypedates megacephalus) is widespread on Hainan Island and yet nothing is known about its history. To investigate this, we use sequences of a partial fragment of mitochondrial ND1 and its flanking region from 248 individuals taken from 30 localities. Analyses reveal low genetic diversity and commonly shared haplotypes. Montane areas exhibit a significantly greater genetic diversity than lowland areas (P 0.01). The origin of P. megacephalus on Hainan Island dates to 1.06 Ma in the Pleistocene. Population expansion events were associated with the transition from the last interglacial period to the last glacial maximum. The matrilineal history indicates dispersal from the montane to the lowland. Bidirectional dispersion occurs between northeastern and southwestern parts of the island. Low FCT values for the northeastern and the southwestern areas associate with rivers, whereas the highest values occur among two geographical groups. Thus, mountains and rivers appear to have effected dispersal. Pleistocene climatic cooling and the creation of a landbridge with mainland China owing to lowered sea levels best explains the occurrence of P. megacephalus on Hainan Island. The analyses provide insights into the effects of Pleistocene climatic fluctuations on an amphibian on Hainan Island.