LATE EOCENE ENTELODONTS (MAMMALIA, ARTIODACTYLA) FROM INNER-MONGOLIA,CHINA

Previously undescribed specimens of Entelodon from the late Eocene (Er gilian) of Nei Monggol, China represent two species, small and large. We identify the small species as Entelodon gobiensis (Trofimov, 1952), because this is the oldest valid name available for a relatively smal l species of Asian Entelodon. E. diconodon (Trofimov, 1952) is a nomen dubium, and it is probable that E. ordosius (Young & Chow, 1956), E. major Biryukov, 1961 and E. orientalis Dashzeveg, 1965 are junior subj ective synonyms of E. gobiensis (Trofimov, 1952). The large species is Entelodon dirus Matthew & Granger, 1923, a species previously known o nly from its holotype M3, but to which we now refer a lower jaw with p 2-m3. In Asia, Entelodon is more common in strata of Ergilian (late Eo cene) age; its Shandgolian (early Oligocene) occurrences are few. Ente lodonts originated in Asia during the middle Eocene, immigrated to Nor th America (late Eocene) and Europe (early Oligocene) and persisted un til late Oligocene in Eurasia and North America. The last entelodonts, from the early Miocene of North America, apparently arose from a sepa rate, latest Oligocene emigration from Asia.