New late Eocene cylindrodontid rodents from the Erlian Basin (Nei Mongol, China)

Three cylindrodontids,Pseudocylindrodon yihesubuensissp. nov.,Ardynomys olseni, andArdynomyssp. from the locality Yihesubu, and the "Middle White" and "Upper Red" beds of the Erden Obo section in the Erlian Basin, Nei Mongol, China, are described.Pseudocylindrodon yihesubuensissp. nov. is the earliest known species ofPseudocylindrodonin Asia, and more advanced than UintanPseudocylindrodon citofluminisfrom Saskatchewan, Canada. The fossils ofArdynomysandPseudocylindrodonin the Erlian Basin suggest that the cylindrodontids-bearing strata are late Eocene, and provide new evidence of mammalian dispersal between Asia and North America during the late Eocene.