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The microwear of the non-occlusal surface of incisors (I1, I2) of the small cave bear (Ursus ex gr. savini-rossicus) and Ural cave bear (Ursus kanivetz) from the Pleistocene of the Middle and South Urals is analyzed and compared. Qualitative characteristics of incisor microwear have been shown to be different in these species. In the small cave bear, coarser lesions on the non-occlusal surface of the incisors are observed. Considering the specificity of microwear of non-occlusal tooth surfaces, the data obtained suggest differences in trophic specialization of the species. studied., (© 2022. Pleiades Publishing, Ltd.)

Enamel macro- and microstructure has been studied in the teeth of Merck's rhinoceros (Stephanorhinus kirchbergensis Jäger, 1839), woolly rhinoceros (Coelodonta antiquitatis Blumenbach, 1799), and rhinoceroses from the Tetyukhinskaya (44°35' N, 135°36' E) and Sukhaya (43°09' N, 131°28' E) caves in southern Primorye. The teeth from the caves were identified as the teeth of Merck's rhinoceros. Radiocarbon dating and accompanying animal species enabled the dating of Merck's rhinoceros remains to the Late Pleistocene (marine isotope stages 5-2). These finds mark the extreme eastern boundary of the Merck's rhinoceros species range in the Late Pleistocene. The living range reached the Pacific Ocean coast during a certain time interval within this epoch. This was due to the abundance of tree and shrub vegetation in the area during the Late Pleistocene.

In small mammals, the degree of micro- and mesowear of molars depends on the feed hardness, abrasiveness, and some other characteristics. Analysis of micro- and mesorelief of the paleontological material is used for reconstruction of some animal diet parameters. Small mammals pass through a series of complex transformations on the way from the objects of biocenosis to paleontological objects. Bone remains underwent transformations during accumulation and fossilization. In particular, bone remains from ornithogenous deposits were exposed to the bird digestive system elements. We have experimentally studied changes in some parameters of the narrow-headed vole (Microtus gregalis) molars derived from the owl pellets. Comparison of the same samples before and after exposure to the digestive system of the polar owl (Nyctea scandiaca) and eagle owl (Bubo bubo) showed that the tooth enamel microrelief undergoes serious changes and therefore, provides no information on the intravital diet of voles. A different degree of preservation of the characteristics of the mesorelief was shown. Depending on this, an assessment of their applicability to paleoreconstructions was given.

In the narrow-headed vole, enamel microwear of the first mandibular molar (of the protoconid and entoconid anterior enamel wall) was studied under the laboratory conditions and at the fixed feed composition. The classic parameters and the area of the enamel prism lesion were taken into account. The enamel lesion patterns caused by the tooth-tooth and tooth-food interactions have been determined. Differences were found between the voles kept on feed with different abrasive properties, as well as between the lingual and buccal conids of the first mandibular molar. In the Microtus species, the ratio of micro-lesions (pits and scratches) did not depend on the abrasive properties of the feed consumed. The extent of preservation of the enamel contour anterior edge depended on the feed composition and could be used as an indicator for indirect evaluation of the Microtus species diet.

In Craseomys rufocanus and Craseomys rex, the age-related and species differences in thickness and microstructure of the first lower molars (ml) have been identified and studied. The results suggest that the enamel dimensional and microstructural features may serve as additional indicators of the vole tooth evolutionary stage within a single phyletic lineage.