Evolutionary history of mountain voles of the subgenus Aschizomys (Cricetidae,Rodentia), inferred from mitochondrial and nuclear markers

In this study, we present an assessment of the evolutionary history and phylogenetic relationships of Asian mountain voles of the subgenus Aschizomys, genus Alticola, based on extensive sampling and phylogenetic analyses of data from mitochondrial and nuclear markers. Two species of this subgenus are widespread in the mountain areas of north‐eastern Asia. However, both their distribution and taxonomic borders remained questionable for more than 100 years. Our study showed discordance in the phylogenetic patterns between nuclear and mtDNA markers. We found that mtDNA in A. lemminus is paraphyletic relative to A. macrotis, but nuclear markers demonstrated reciprocal monophyly. According to species distribution modeling, ranges of A. macrotis and A. lemminus experienced a secondary contact during the Last Glacial Maximum (approximately 22 kyr BP), and thus a hybridization event seems plausible during that period. Species tree analyses recovered a sister group relationship between the two species of the Aschizomys subgenus, with an estimated divergence date of around 0.8 Ma. Our results provided good support for currently recognized subspecies within both A. macrotis and A. lemminus based on mitochondrial and nuclear datasets. A new, yet undescribed form, supposedly of a subspecific status within A. lemminus, was found in the Bureinskiy Range in the Khabarovsk area. This finding expands the current species distribution range further to the southeast.