thought to closely related to, but outside, Rauisuchia. In their tree, Poposauroidea included genera usually classified as poposauroids as well as several other genera that were not previously placed in the group. One of these genera, Qianosuchus, is unique among pseudosuchians in its semiaquatic lifestyle. In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt (2011) found Xilousuchus to be a poposauroid most closely related to Arizonasaurus. Nesbitt's analysis did not recover a monophyletic Rauisuchia or monophyletic Rauisuchoidea. Poposauroidea was found to be monophyletic, and more resolved than in previous analyses, with Qianosuchus as the most basal member of the group and Lotosaurus'' grouping with shuvosaurids instead of ctenosauriscids. The cladogram below follows Nesbitt (2011) with clade names based on previous studies. References External links Poposauroidea in the Paleobiology Database Early Triassic first appearances Rhaetian extinctions Taxa named by Franz Nopcsa von Felső-Szilvás Fossil taxa described in 1923