A new species of Largocephalosaurus (Diapsida: Saurosphargidae), with implications for the morphological diversity and phylogeny of the group

摘要: Largocephalosaurus polycarpon Cheng et al. 2012a was erected after the study of skull and some parts a skeleton considered to be an eosauropterygian. Here we describe new species genus, qianensis, based on three specimens. The provides many anatomical details which were described only briefly or not at all in type species, clearly indicates that is saurosphargid. It differs from mainly having premaxillary teeth, very short retroarticular process, large pineal foramen, two sacral vertebrae, elongated small granular osteoderms mixed with ones along lateral most side body. With additional information revise diagnosis phylogenetic relationships clarify set diagnostic features for Saurosphargidae Li 2011. characterized primarily by oval supratemporal fenestra, elongate dorsal rib-basket', narrow transverse process lack complete carapace osteoderms. distinct retracted external naris, jugal-squamosal contact, extensively contacting quadrate shaft, leaf-like tooth crown convex labial surface concave lingual surface, closed osteoderms, boomerang-like atypical T-shaped interclavicle. Current evidence suggests sister-group Sauropterygia Saurosphargis-Sinosaurosphargis clade within family.