Vertebrate fossils at PEFO are restricted to the Petrified Forest Formation. Our surveys have resulted in the discovery of a significant new dinosaur locality named Dinosaur Ridge. A smaller species is represented by several specimens including phalanges, vertebrae and tooth-bearing cranial and dentary fragments. The associated fauna is dominated by small tetrapods including several osteoderms of the small aetosaur Acaenosuchus geoffreyi and sphenosuchian vertebrae. Larger vertebrates are represented by fragmental bones and teeth of phytosaurs.
Vertebrate coprolites are common.
Dinosaur Ridge represents a overbank mudstone, subject to a fluctuating watertable, that has been pedogenically modified. Color-mottling, carbonate concretions and permineralized roots attest to the paleosol origin of this bed. Dinosaur Hill represents an abandoned channel deposit that was subject to seasonal ponding and pedogenic alteration. Other specimens included a skull and postcrania of the small metoposaurid Apachesaurus and undescribed specimens of a smaller theropod dinosaur. In addition, we have collected the most complete known vertebral column of the small amphibian Apachesaurus .