Large mammals of the middle and late Pleistocene from the alluvial sites of Bibikha at the Ob river (Novosibirsk region) and from the Chumysh river (Altai krai)

In 2019, two large secondary alluvial sites in the vicinity of the village of Bibikha on the Ob River and between the villages of Martynovo and Kytmanovo on the Chumysh River continued to be explored. During five years of research, 5471 speciments of bone remains belonging to 19 species of large mammals have been collected in Bibikha. The remains of the Middle Pleistocene belong to Castor fiber, Canis lupus, Ursus arctos, Ursus savini, Panthera leo spelaea, Mammuthus primigenius, Equus ferus Equus ferus (ex. gr. mosbachensis-germanicus), Stephanorhinus kirchbergensis, Coelodonta antiquitatis, Camelus knoblochi, Megaloceros giganteus, Cervus elaphus cf. sibiricus, Rangifer tarandus, Bison priscus and Saiga tatarica borealis. Bones ended up on the beach from the Middle Pleistocene riverbed alluvium eroded by the river below the water edge. A small part of the material evidence belongs to the Early Pleistocene species, such as Panthera leo mosbachensis, Cervalces latifrons, Praeovibos sp., Soergelia cf. elisabethae. In Bibikha, bone remains of bisons and horses were the most numerous (52 and 25.8 % respectively). The total number of bone remains collected in the course of ten years at the Chumysh River amounted to 14,757 pieces belonging to 29 species of megafauna. The vast majority of bones which had been washed out of the sediments of the second terrace above floodplain, were dated by 14C to the Karginsky and Sartan periods. Bones of bisons and horses predominated (47.5 and 22.5 % of remains). In 2019, the list of species at the Chumysh River was enriched with individual bones of Marmota baibacina, G. gulo, Sus scrofa, and Ovis ammon. This is the first find of a boar from the Pleistocene in the southeastern Western Siberia. Argali lived on the spurs of the Salair Ridge in the Late Pleistocene. Theriocomplexes of the Middle Pleistocene at Bibikha and of the Karginsky period at the Chumysh River inhabited the dominant forest-steppe landscapes.