Fossil vertebrates of Skelia Podil’ska 2 (Dnister area, Ukraine): a distinctive interglacial fauna of the Early Chibanian

Abstract

A new microvertebrate assemblage from Skelia Podil’ska 2 (Ternopil Oblast, the Dniester area, Ukraine) sheds light on faunal evolution during the Martonosha interglacial (Early Chibanian, Pleistocene). The fauna was discovered beneath a small rock shelter developed in the Shyrokyne alluvial sandstones. The section comprises alluvial and subaerial deposits of the Zbruch valley, and records several palaeoincisions of different ages. The oldest, Martonosha palaeoincision, formed a cliff face hosting a small rock shelter in which the fossils were recovered. Taphonomic analysis of the findings and their palaeogeomorphological context indicates that the bones accumulated due to owl activity. The fossil assemblage includes amphibians and rodents and is taxonomically and ecologically attributable to the Kolkotovian association of the Tiraspol fauna (MIS 17). The fauna is characterised by the absence of steppe and semi-desert species, and by a pronounced dominance of the subgenus Terricola voles, particularly Microtus (Terricola) arvalidens. Amphibian remains constitute an unusually high proportion of the assemblage. Ecologically, the assemblage reflects warm and highly humid climatic conditions typical of the Martonosha interglacial. At the same time, the scarcity of strictly forest-associated vertebrates suggests that closed forests were locally poorly developed. This discrepancy is attributed to shallow limestone and sandstone bedrock, which limited forest development despite favourable climatic conditions.