New data on the skull of Protorosaurus speneri and their phylogenetic significance

The late Permian (Lopingian) reptile Protorosaurus speneri has long been considered the earliest-diverging archosauromorph. Although it is known from extensive skeletal material from the Kupferschiefer of the Werra Formation of Germany, its skull has remained incompletely known. Extensive preparation and CT scanning of a referred skull have provided much additional information on the cranial structure, especially the basicranial and palatal regions. Phylogenetic analysis integrating the new anatomical data supports the hypothesis that Protorosaurus speneri is the earliest-diverging archosauromorph to date.

Methods
Morphological character-states, based on a re-examination of the skull of Protorosaurus speneri. Primary focus on the mandible, palate and dnetiotion. CT data and their segmentation formed an important part of this study.