Egorov’s narrow-skulled vole (Rodentia, Arvicolinae) from the Late Pleistocene of Eastern Siberia, a North American immigrant

A comparative study of the Late Pleistocene Egorov’s narrow-skulled vole from the Indigirka River basin is performed. The taxon was previously regarded as a subspecies of Microtus (Stenocranius) gregalis (Pallas, 1779). Based on a number of morphological characters, it is shown that this vole is closer to the American species Mynomes (Vocalomys) miurus (Osgood, 1901). It is proposed that Mynomes (V.) miurus egorovi (Fejgin in Baranova et Fejgin, 1980) penetrated into northeastern Siberia during the Zyryanian glacial.