Small mammal assemblages from paleosols in Eastern Europe indicate evolutionary trends and predominantly warm and dry climates across Middle and Late Pleistocene Interglacials

Abstract

We studied nine local small mammal faunas directly recovered from interglacial (and one interstadial) paleosols of the Middle (seven) and Late (two) Pleistocene on the East European Plain. The oldest faunas, dated to the Muchkap (MIS 15) and Likhvin (MIS 11) interglacials, belonged to the Late Tiraspolian and Gun'ki small mammal complexes, respectively. Later faunas, corresponding to the Kamenka, Romny, and Mezin paleosols, included chronotaxa morphologically close to modern species. The youngest Middle Pleistocene fauna most likely correlates with the Romny interglacial (MIS 7). The youngest overall fauna dates to the Bryansk (=Denekamp) interstadial (late MIS 3). We performed the first comprehensive analysis of the quantitative composition of these faunas using multivariate analysis and inferred qualitative relationships among them. The main component of variation in faunal composition identified by non-metric multidimensional scaling (first NMDS axis) reflects evolutionary changes in the phyletic lineages of steppe lemmings (Lagurus) and narrow-headed voles (Stenocranius). The other two components correlated with the geographical position (longitude and latitude, respectively) of the sections, most likely reflecting a relatively stable pattern of variation in ecological conditions across the East European Plain. The faunal composition suggests that the animals inhabited semi-arid and arid steppe habitats, and that the paleosols formed during the warmest and driest phases of the interglacials in Eastern Europe. The non-analog Bryansk interstadial complex is associated with conditions of periglacial, mosaic steppe–tundra-like environments. Based on the analysis of the small mammal faunas, we also present a biostratigraphic scheme for the Middle and Late Pleistocene of the central and southern parts of the East European Plain (Eastern Europe).