Reassessment ofPlatyognathus hsuiYoung, 1944 (Archosauria: Crocodyliformes) from the Lower Lufeng Formation (Lower Jurassic) of Yunnan, China

Abstract

ABSTRACT The holotype of Platyognathus hsui Young, 1944, an incomplete mandible from the Lower Jurassic Lower Lufeng Formation of Yunnan (China), was lost or destroyed during World War II. Material subsequently referred to this taxon actually represents a different taxon of basal Crocodyliformes, and some authors have recently questioned the validity of P. hsui. A partial skull collected in 1984 is referable to P. hsui and is designated as a neotype. It corroborates most of the features originally used by Young to diagnose P. hsui and provides additional diagnostic characters for that taxon. P. hsui can be distinguished from other basal crocodyliform taxa primarily by the fused mandibular symphysis, large caniniform teeth in positions 5 and 6 in the dentary, and the polygonal cross-section of (at least) the sixth dentary tooth. P. hsui is referred to the Protosuchia sensu Wu et al. (1994).