Ground squirrels of the genus Spermophilus from the Pleistocene and Holocene localities of the Middle and South Urals and Trans-Urals region: the dental features

Abstract

ABSTRACT The dental features of fossil Spermophilus from eleven Pleistocene and Holocene localities of the Middle and South Urals and Trans-Urals region are described. The comparison with the recent species S. major, S. fulvus and S. pygmaeus from the same region was carried out. The most important features of the recent and fossil S. pygmaeus are: small and medium sizes; metaloph of P4-M2 bear constrictions or interruptions, metaconule is well pronounced and rounded; anterostyle often is well developed in P4; high frequency of meso- and metastylid in m1-3. In M3 the anterior inner and posterior roots are close together and tend to merge with each other in their upper parts. Also, S. major was a part of the Late Pleistocene and Holocene faunas. The most important features of S. major are: medium and large sizes; a small number of P4-M2 with the occlusal cusps, among them the most significant is the presence of parastyle; in m1-2 mesostylid commonly occurs. The tendency to complication of the root part of M3 of S. superciliosus is revealed from Late Pleistocene to Holocene. The comparison with the fossil S. superciliosus from Eastern Europe was carried out. No significant differences between S. superciliosus and S. major were found.