2010/06/25 by Ke‐Qin Gao, Richard C. Fox, Chang‐Fu Zhou +1 · 2 citations
Earth and Planetary Sciences · Environmental Science · #Paleontology and Evolutionary Biology #Ichthyology and Marine Biology #Amphibian and Reptile Biology
paper · doi:10.1206/649.1
openalex publication_date 2010/06/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
A new trirachodontid eucynodont, Beishanodon youngi, is named and described based on a well-preserved skull from Triassic lacustrine deposits exposed in the Beishan Hills, northern Gansu Province, China. The new discovery documents the second record of trirachodontid eucynodonts known from China, along with Sinognathus gracilis from the Middle Triassic Ermaying Formation exposed in Shanxi Province. Cladistic analysis supports the placement of the new taxon as the sister group of Sinognathus, and the two together can be classified in Sinognathinae, a new subfamily differentiated from other trirachodontids by possession of several derived character states, including extremely short snout and strongly expanded temporal region. In addition, the stratigraphic and biogeographic significance of the new discovery are discussed. Because trirachodontids have a restricted stratigraphic range in the Triassic, as best documented by the Cynognathus Assemblage Zone of South Africa, discovery of the new fossil of this group from northern Gansu Province in China provides definitive evidence for a Triassic age of the fossil-bearing beds exposed in the Beishan Hills; moreover, the fossil beds are assessed as Early Triassic in age based on the evidence from the entire vertebrate fauna.