Analysis of North American goniopholidid crocodyliforms in a phylogenetic context

Goniopholididae is a distinctive and common clade of crocodyliforms known from the Jurasic and Cretaceous of Europe, Asia, and North America. Their position within Neosuchia makes them makes them very important to the study of crocodyliform evolution, but unfortunately their phylogenetic status is ambiguous.

This study describes the osteology of two North American fossil taxa: Amphicotylus stovalli, a previously under-represented goniopholidid from the Jurassic Morrison Formation of Oklahoma, and new material of Denazinosuchus kirtlandicus from the Cretaceous Kirtland Formation of New Mexico. A phylogenetic dataset is then constructed including a full sampling of Jurassic North American forms and incorporating new new goniopholidid taxa not previously treated in a phylogenetic context. The affinity of North American and European members of Goniopholis is assessed as are the taxonomic status of putitive goniopholidids Vetisuchus and Denazinosuchus.

Goniopholididae is monophyletic, and North American goniopholidids form a nested clade united by a distinctive palate morphology. Furthermore, all Morrison Formation goniopholidids are further nested in the North American clade. North American "Goniopholis" are generically distinct from European forms, and should be ascribed to Amphicotylus. Amphicotylus gilmorei is a junior synonym of A. lucasii. Denazinosuchus and Vectisuchus are not constituents of Goniopholididae, and instead are more closely related to pholidosaurs and thalattosuchians.