Abstract:
An almost complete skull with teeth of Archaeoryctes euryalis sp. nov., one of the earliest members of the family Didymoconidae, is described from the Tsagan-Khushu locality in Mongolia (Upper Paleocene, Naran Bulak Formation, Zhigden Member). Examination of the specimen corroborates data on the cranial features of the Didymoconidae, previously based only on of relatively fragmentary material, and enlarged the characteristics of the family. Judging from the skull structure, didymoconids belong to the Insectivora sensu lato; however, substantial differences from the Lipotyphla and Leptictida suggest that they should be ranked a separate order, the Didymoconida ordo nov.
