Advances in Late Triassic Vertebrate Paleontology Based on New Material from Petrified Forest National Park, Arizona

Recent collecting of vertebrate fossils in Petrifi ed Forest National Park as the result of an ongoing inventory of fossil localities has produced numerous important new specimens. These include phytosaur skulls and partial skeletons, aetosaur partial skeletons and isolated, but complete, osteoderms, as well as new dinosaur material that contributes new information to a currently poor dinosaur record from the Late Triassic of Arizona. Stratigraphic placement of phytosaur and aetosaur fossils from the park shows that several index taxa used for Late Triassic land vertebrate faunachrons overlap and that revision of these faunachrons is needed.