Pteranodontid

Modern researchers differ in their use of the concept. S. Christopher Bennett and Alexander Kellner have concluded that Nyctosaurus was not a pteranodontid. In 1994 Bennett defined a clade Pteranodontidae, also including species of the Ornithocheiromorpha. However, this definition has not been accepted by other workers. Alexander Kellner, for example, named several additional species for specimens previously classified as Pteranodon, and placed P. sternbergi in a distinct genus, Geosternbergia. Kellner re-defined Pteranodontidae as the most recent common ancestor of Pteranodon longiceps, Geosternbergia sternbergi and Dawndraco kanzai, and all of its descendants. This definition is now contentious, however, as the validity of Dawndraco has been disputed. This clade possibly includes the nyctosaurids. Analyses by David Unwin did indicate a close relationship between Pteranodon and Nyctosaurus, and he used the name Pteranodontia for the clade containing both.