Andrei Valerievich Shpansky

The history and palaeoecology of the steppe bison ( Bison priscus ) remain incompletely understood despite its widespread distribution. Using dental microwear textural analysis (DMTA) and vegetation modelling, we reconstructed the diet and assessed the habitat of steppe bison inhabiting Eurasia and Alaska since the Middle Pleistocene. During the Late Pleistocene, steppe bison occupied a variety of biome types: from the mosaic of temperate summergreen forest and steppe/temperate grassland (Serbia) to the tundra biomes (Siberia and Alaska). Despite the differences in the identified biome types, the diet of steppe bison did not differ significantly among populations in Eurasia. DMTA classified it as a mixed forager in all populations studied. The DMTA of Bb1 bison—a recently identified genetically extinct sister-clade of Bison bonasus —was typical of a highly grazing bovid species and differed from all B. priscus populations. The results of the study temper the common perception that steppe bison were grazers in steppe habitats. The dietary plasticity of the steppe bison was lower when compared with modern European bison and may have played an important role in its extinction, even in the stable tundra biome of eastern Siberia, where it has survived the longest in all of Eurasia.

The outcrop of the Upper Pleistocene sediments in Sergeyevo is described (57 degrees 15'15 '' N, 86 degrees 05' E), in the middle reach of the Chulym river (Tomsk region; West Siberian plain). It includes two bone-beds. The richest remains of large mammals are the deposits of layer 4. The layer is represented by an alternation of brown loams and bluish-gray clays (the thickness of loam layers is 0.3-1.0 cm, clay layers - 1-3 cm) with ochreous spots and spots of carbon-bearing detritus. Loams are sanded and replaced with red sand in the lower part of the layer. The thickness of clay layers is increased down the section up to 20 cm. Loams become darker (change their color from gray-brown to black) and include numerous fragments of fossil tree trunks and branches in the middle part of the outcrop. Remains of large mammals from mammoth complex (from 13 species) are confined to the upper border of these loams. Various malacofauna and palynological data were obtained from the deposits in addition to theriofauna. Radiocarbon dates obtained from the skull fragment of Coelodonta antiquitatis - 32100 +/- 390 years (COAH-5552) and the metacarpal bone of Panthera spelaea Goldf - 34280 +/- 737 (UBA-38455) indicate the Karginsk period (MIS 3) of layer 4 deposit accumulation. The outcrop (layer 4) is proposed as a basis for Karginsk horizon deposits. It has the following important characteristics: 1) constant upgrading and good exposure of the section; 2) good attachment to the layers (only insite material was found) of paleontological remains; 3) high richness (with annual finds) of mammal remains, their good preservation and reliable taxonomic definition; 4) significant taxonomic diversity of mammal remains, malacofauna and spore-pollen spectra; 5) good combination of results of radiocarbon dating, biostratigraphic, paleogeographic and paleoecologic data.

New findings of Stephanorhinus kirchbergensis in Siberia

A lower jaw of Stephanorhinus kirchbergensis from the Mus Khaya locality on the Yana River in Yakutia is described. This jaw was previously designated as a paratype of Coelodonta jacuticus, but...

Ursus arctos is a large carnivore and a common species for Western Siberia. The earliest traces of it date back to the Middle Pleistocene. During the Holocene, its population grew and its range significantly extended northwards. The modern West Siberian habitat lies between 55° and 67°N, and its dynamics are being affected by human activity and climate change. The beginning of the twenty-first century has been marked by the growth of the population of the brown bear and its occurrence in unusual habitats. Earlier studies of the population genetic structure prove the existence of a Pleistocene refugium on this territory. The body size of the West Siberian brown bear is the largest for U. arctos subscpecies within its range.