The first record of spelaeoid bears in Arctic Siberia

For a long time, spelaeoid (cave-bear-like) bears, Ursus (Spelearctos) spp., were believed to be almost purely European animals. Their geographic range has recently been extended to the east, in southern Siberia, Transbaikalia, Kirghizia, Mongolia and Korea. Two unexpected new findings, presented here in detail, significantly change existing views on the distribution of cave bears; both were found in North-Eastern Siberia, far beyond the Arctic Circle, more than 1500 km to the north-east of the previously accepted range. One of the fossils is a mandible, found near the town of Cherskiy at 68.73 degrees N, 161.38 degrees E. The analysis of local geology and accompanying mammal fossils suggests that it comes from the Olyorian Fauna (Early to early Middle Pleistocene). Morphologically, the Cherskiy mandible is closest to Ursus savini, a small middle Pleistocene cave bear from the British Cromer Forest-bed Formation, but differs in having a slightly more advanced dentition, and thus it is described as a new subspecies Ursus savini nordostensis. Another newly recognized fossil of the spelaeoid bear is an astragalus found at the Oskhordokh site at 67.54 degrees N, 135.67 degrees E, on a large gravel bar on the right bank of the Adycha River. This specimen is attributed to Ursus cf. deningeri. The paper also presents an interesting example of the interaction between classical and molecular palaeontology. The new finds significantly change existing ideas on the ecology and evolution of cave bears, some of the most remarkable members of the extinct Pleistocene megafauna. (C) 2010 Elsevier Ltd. All rights reserved.