Non-occlusal incisor microwear in Ursus rossicus Borissiak, 1930 and U. k. kanivetz Vereshchagin, 1973

A comparative microwear analysis was conducted on the non-occlusal surfaces of incisors (upper I1, I2) from Ursus rossicus and U. k. kanivetz recovered from Pleistocene deposits in the Middle and Southern Urals. For comparison, the non-occlusal surfaces of incisors from Pleistocene and Holocene U. arctos were also subjected to microwear analysis. Interspecies differences were established. Ursus rossicus exhibited coarser microwear features on the labial (anterior) non-occlusal surfaces of its incisors. Considering the specific nature of non-occlusal dental microwear, the data obtained lead to inferences regarding differences in diet specialisation between the studied species. Apparently, U. rossicus may have consumed coarser, tougher, drier vegetation, engaged more frequently in rhizophagy and had distinct foraging behaviour compared to other cave and brown bears. This interpretation is supported by stable isotope analysis (δ1 3 C and δ1 5 N), the distinct form and size of U. rossicus incisors, and this species’ inferred preference for more open habitats. Our research further indicates that a comprehensive characterisation of ursid foraging behaviour is only achievable through a combined analysis of microtextural features across all incisor and cheek tooth surfaces, encompassing both occlusal and non-occlusal aspects.