EARLY MIOCENE RODENTS FROM THE AKTAU MOUNTAINS (SOUTH-EASTERN KAZAKHSTAN)

Abstract

The rodent assemblage from the Middle Members of the Chul’adyr Formation contains seven species that belong to six (sub)families. The dominant Cricetidae are represented by a new genus and species:Aktaumys dzhungaricus and by a new species ofKarydomys: K. dzerzhinskii. Each of the other rodent species: ?Sinosminthus gen. et sp. indet.,Sayimys aff.obliquidens, Asiacastor aff.baschanovi and Tachyoryctoidinae gen. A, sp. 1, is represented by a few cheek teeth only (altogether 8% of the specimens). The composition of the assemblage resembles Oligo-Miocene material from Anatolia, but the closest relatives of most of the species are found in Central Asia. The stage of evolution ofKarydomys dzerzhinskii, Sayimys aff.obliquidens and the tachyoryctoidine suggests an Early Miocene (MN4 rather than MN3) age for the assemblage.