RODENTS FROM THE EARLY PALEOGENE DZHYLGA LOCALITIES IN SOUTHERN KAZAKHSTAN

Abstract

Two isolated molars, the holotypes of Asiaparamys shevyrevae NESSOV, 1987b and Kazygurtia clivosa NESSOV, 1987b from the latest Paleocene Dzhylga 1 a locality are restudied, and an additional molar of A. shevyrevae from the same locality is described. Asiaparamys is referable to the rodent family Ischyromyidae by having the trigonid compressed antero-posteriorly and a ridge-like hypoconulid. Kazygurtia with a posteriorly closed trigonid basin, subvertical posterior trigonid wall, weak ectolophid lacking a mesoconid, cusp-like hypoconulid, and strongly bunodont molar cusps, is one of the most generalized Glires taxa; it is referred to Glires incertae sedis. The Glires species from Dzhylga 1a are among the oldest known rodents or rodent-like mammals. Enamel microstructure of five isolated Glires incisor fragments exhibits two-layered enamel with pauciserial Hunter-Schreger bands and radial enamel, which are typical for early Paleogene rodents.