MIS3 – MIS2 transition based on small mammal faunas from Palaeolithic sites in the centre of the East European Plain

Palaeontological methods, including the study of fossil small mammals (Lagomorpha, Rodents, Eulipotyphla), are instructive for paleoenvironmental reconstructions. This paper presents results of fossil small mammals' investigation in cultural layers of six Late Pleistocene sites related to Middle and Upper Palaeolithic. In addition to prehistoric sites at Betovo, Khotylevo 2, Eliseevichi 2, Yudinovo, Novgorod Severskaya, and Byki 7, we analyse two synchronous Late Pleistocene natural faunal localities in Arapovichi and Troitsa 2, all in the centre East European Plain. The main aim of this paper is to reconstruct the transition of the regional small mammal fauna from the end of MIS 3 (the so-called Bryansk = Denekamp Interstadial) to the Last Glacial Maximum (LGM) of Marine Isotope stage 2 (MIS2) (∼32–17 ka BP). All small mammal assemblages show low species richness (3–16 taxa), with cold adapted tundra and steppe animals dominating, while forest mammals are rare or practically absent. Palaeozoological data indicate the existence of mosaic periglacial landscapes in the area, such as complicate composition of shrub tundra-like and periglacial steppe. The three-dimensional descriptive model reproduces changes in local faunal (LF) composition caused by the general climate trend during the transition from interstadial conditions at the end of MIS3 to the extremely cold conditions of the LGM (mid-MIS2). We distinguish four main phases of this transformation: phase I that corresponds to the end of MIS3 and the beginning of MIS2 and is characterised by the dominance of Dicrostonyx sp., relatively low occurrence of Lasiopodomys anglicus/gregalis, low occurrence of Ochotona pusilla; the next phase II is characterised by some decrease of Dicrostonyx sp. remains but the increase of L. gregalis. Phase III corresponds to the most severe climatic conditions in the GS-2.1 stadial. The youngest fauna of the Yudinovo site is characterised by the dominance of the collared lemming and the narrow-headed vole and corresponds to phase IV and the end of the LGM.