摘要：The tetrapod assemblage from the Middle Triassic upper part of the Ermaying Formation of northern China has been known for two decades as the SinokannemeyeriaShansisuchus Assemblage because of the characteristic presence of the dicynodont therapsid Sinokannemeyeria and the erythrosuchid archosauriform Shansisuchus. Recently a Sinokannemeyeria species has been described from Member I of the Tongchuan Formation, which overlies the Ermaying, near Baidaoyu, Linxian, Shanxi Province. Here we document archosauriform specimens from the Baidaoyu site, including a partial Shansisuchus skeleton and some additional bones from probable suchian archosaurs, which constitute the fi rst archosauriform material known from Member I of the Tongchuan. The most intriguing archosauriform specimens are a large ilium probably attributable to an unusual poposauroid, and a small, strangely shaped element that appears to represent a highly autapomorphic suchian calcaneum. Given the presence of both Sinokannemeyeria and Shansisuchus at Baidaoyu, the stratigraphic range of the Sinokannemeyeria-Shansisuchus Assemblage can be considered to extend upward into the Tongchuan Formation, although with possible changes in faunal composition. The occurrence of a poposauroid ilium at the Baidaoyu locality adds to the evidence that poposauroids diversifi ed extensively during the Middle Triassic.