Phytosaurs (Reptilia: Archosauria) from the Upper Triassic New Oxford Formation of York County, Pennsylvania

ABSTRACT

An incomplete well-preserved skull of a small phytosaur from the Upper Triassic New Oxford Formation of York County, Pennsylvania, resembles skulls previously referred to Rutiodon carolinensis in the plesiomorphic possession of a slender, uncrested rostrum. It differs from the latter only in the course of the palatal suture between the premaxilla and maxilla and the sharply notched anterior margin of the supratemporal fenestra. The type species of Rutiodon Emmons, 1856, R. carolinensis from the Cumnock Formation of North Carolina, cannot be adequately diagnosed at present and is considered a metataxon sensu Gauthier (1986). A very large tooth of a phytosaur from the same locality as the skull is not conspecific with the latter and indicates the existence of a second, much larger phytosaur in the New Oxford Formation.