Abstract: Eotitanosuchia is a primitive suborder of Therapsida. Carroll (1989) included three families, Biannosuchidae, Eotitanosuchidae and Phthinosuchidae in this suborder, while Sigogneau—Russell (1989) assigned only one family Eotitanosuchidae including two genera and two species. Eotitanosuchus olsoni Chudinov, 1960 and Ivantosaurus ensifer Chudinov, 1983. The two genera come from the Upper Kazanian, Esheevo Locality, Ocher Province, Russia. A recently discovered incomplete skull and mandibles from Upper Permian Xidagou Fonnaüon, Dashankou Locality, Gansu are described here as the first eotitanosuchian outside Russia. Associated with this taxon are numerous therapsids, labyrinthodont amphibians and captorhinomorphs, of which a bolosaurid Belebey vegrandis, two dinocephalians Sinophoneous yumenensis and Stenocybus acidentatus have been reported (Li and Cheng, 1995; Cheng and Ji, 1996; Cheng and Li, 1997). The discovery of eotitanosuchian in China further proves close relationships between the mshankou Fauna and the Zone Il of Russia, and provides new material for discussing the phylogeny of early therapsids.

摘要： 记述了始巨鳄亚目的一个新属新种祁连双列齿兽(Biseridens qilianicus)。标本产自甘肃玉门大山口上二叠统的西大沟组。Biseridens以中等大小的头骨，短的眶前区，粗大的顶骨结节和大的顶孔，形态独特的颊齿和双排齿列，有别于体型硕大，肉食习性的Eotitanosuchus。动物群的分析表明，大山口低等四足类动物群与俄罗斯上二叠统卡赞阶II带的脊椎动物组合有较为密切的关系。