New finds of pleistocene large mammal remains from secondary alluvial locations in the Upper ob Region in 2021

The total of1584 bone remains from 18 large mammal species were collected on the Chumysh River of the Altai Region, and 492 from 14 species on the Chik River in 2021. 1259 bone remains from 14 species of Pleistocene megafauna were collected on the beach near the village of Bibikha. The taphonomic features of the studied localities are considered. Bones have not been found in the sandy-pebble strata of the beaches. All bones on the beaches lie on the surface, or they are partially submerged in the sub-surface layer. According to the data of radiocarbon analysis, the theriofauna from the Chumysh and Chik dates back to the second half of the Late Pleistocene - Karginian; Sartanian to a lesser extent. In Bibikha, most of the finds belong to the Middle Pleistocene, fewer bones - to the Early Pleistocene. Described are rare finds of bones of the Pleistocene megafauna, in particular bones of Ursus arctos and Ursus savini, cave lion, Soergelia. Comparison of measurements of the mandibular of the Middle and Late Pleistocene cave lions of the Upper Ob region showed a slight decrease in the size of the body of Panthera leo spelaea during that time. An astragalus of a giant brown bear was found at Bibikha. In size, it is much larger than the astragalus of the Holocene brown bear and Ursus spelaeus. Perhaps this astragalus belongs to an especially large individual of the largest Middle Pleistocene subspecies Ursus arctos kamiensis. Over the years of the study, the following collections were assembled: from the Chumysh - 17381 bone remains from 27 species, the Chik - 4128 bones from 18 species, and at Bibikha - 6969 items from 20 species of large mammals.