The taxonomy and systematics of Parapsicephalus purdoni (Reptilia: Pterosauria) from the Lower Jurassic Whitby Mudstone Formation, Whitby, U.K

The Lower Jurassic (Toarcian) pterosaur Parapsicephalus purdoni Newton, 1888 from the Whitby Mudstone Formation of North Yorkshire is known from a three-dimensionally preserved skull with a three-dimensional endocast of the brain. Since Newton’s original description, its taxonomic status has been contentious. Several cladistic studies have placed it within either Dimorphodontidae or Rhamphorhynchidae. Some investigators have suggested that it is a junior synonym of the Toarcian pterosaur Dorygnathus from the Posidonia Shale of south-western Germany. The holotype skull (GSM 3166) is redescribed and its taxonomic status re-evaluated. Several apomorphies suggest it belongs in the Rhamphorhynchidae while autapomorphies of the palate and jugal distinguish Parapsicephalus from Dorygnathus, supporting the continued separation of the two genera.