New data on the distribution and intraspecific variation of the Millard’s giant rat Dacnomys millardi (Mammalia, Rodentia) from Vietnam

The paper presents an analysis of a genetic and morphological variation of Dacnomys millardi from seven Vietnamese localities, including a new finding from southern Vietnam which lies some 1000 km to the south of the currently known limit of the species range. Samples from northern and southern Vietnam do not differ significantly in their cranial and oversize characteristics. Surprisingly, they are quite similar genetically as well. The genetic distances between the samples are very low and do not exceed 0.0232 for cyt b, 0.0058 for subunit I of the cytochrome oxidase gene, 0.0019 for interphotoreceptor retinoid-binding protein, and 0.0017 for recombination activation factor gene. A low overall genetic diversity in the D. millardi could reflect its ecological specialization, as well as a population bottleneck or the colonization history of eastern Indochina.