Аннотация:We review the entelodontid artiodactyl fauna of the upper Eocene Ergilin Dzo Formation in southeastern Mongolia. Also, we describe new specimens of Brachyhyops trofimovi from the Khoer Dzan locality and review the characteristics and Asian distribution of Brachyhyops. The revised entelodontid fauna of the formation consists of three species: Entelodon gobiensis (from the Khoer Dzan and Ergilin Dzo localities), Brachyhyops trofimovi (from the Khoer Dzan locality), and Brachyhyops? sp. (from the Ergilin Dzo locality). The discovery of p4 and M2 of B. trofimovi demonstrates the definitive diagnostic characteristics of this species within the genus: p4 is buccolingually wide and is triangular in occlusal view; it has a well developed and high cusp (= hypoconid?), which is fused to the posterior part of the protoconid; and M2 has a better-developed pericone. In Asia, Brachyhyops is recorded only in the southern part during the middle Eocene and only in the northern part during the late Eocene, implying that the genus originated in the southern part of Asia and subsequently migrated northward, giving rise to northern Asian and North American Brachyhyops.
