New Permian therocephalians from China.

LIU, J.; ABDALA, F.

Calgary

Conferencia; 77th Annual Meeting of the Society of Vertebrate Paleontology; 2017

Society of Vertebrate Paleontology

Therocephalians were important component of middle to late Permian terrestrial faunas in Russia and Africa. Even the Chinese Permian is well represented, this therapsid lineage has a very elusive record in China. The therocephalian Urumchia lii was original reported as late Permian in age, but further studies demonstrated that it really come from the Early Triassic Jiucaiyuan Formation. Recent prospective works resulted in the discovery of several therocephalians, remarkably increasing the diversity of this therapsid group in the late Permian of China. Dalongkoua fuae, represented by an incomplete skeleton from Bed 40 of the Guodikeng Formation, is a new eutherocephalian on the basis of the following characters: maxillary ventral margin is strongly concave in lateral view; incisors spatulated and rounded; coronoid process of the dentary with a marked adductor fossa; triangular reflected lamina with two concavities. In addition to this, at least three new species of therocephalians are documented in the Naobaogou Formation, Nei (Inner) Mongolia. The first one is represented by a snout missing its dorsal edge, featuring a nicely preserved palate. Themorphology resemble to akidnognathid therocephalians, most particularlyAnnatherapsidus from Russia. A phylogenetic analysis recover this Chinese in apolytomy with Perplexisaurus, (Chthonosurus, Ichibengops) and Akidnognathidae. The second one is represented by a nearly complete skull with lower jaws, and it is a typical akidnognathid. The third therocephalian is a partial skull with lower jaws and the left humerus. The braincase is well-preserved and prepared. Its phylogenetic position could not be determined, and more work needs to be done to resolve it. Current phylogenetic results do not support a close (sister) relationship of Chinese and Russian species.