LAUSR

The external morphological, X-ray, and tomographic study of a frozen rodent mummy from the Upper Pleistocene Yedoma deposits on the Tirekhtyakh River (a Semyuelyakh River tributary, Abyi ulus, Republic of Sakha (Yakutia), Russia) showed its belonging to Lemmus sp. The radiocarbon age of the finding is 41 305–41 885 cal B.P. This is the first Pleistocene discovery of a frozen mummy of a genus Lemmus representative. In terms of the body and skull sizes, coat color, the lower incisor length, and the molar structure, the specimen studied is similar to the recent Lemmus sibiricus (Kerr, 1792). Comparison of the mitochondrial COB gene sequence with the DNA sequences presented in the GenBank database also testified to the maximum similarity with the Recent Siberian brown lemming.