Placerias Quarry of eastern Arizona have been assigned to this species. The rocks that D. gregorii is known from are older than those romeri has been found in. As with the Hayden Quarry, the Otis Chalk Quarry has at least one specimen of a herrerasaurid. Dromomeron gigas A third species, D. gigas, was described by Martínez et al. (2016) on the basis of fossils recovered from the Norian Quebrada del Barro Formation in northwestern Argentina. Paleoecology Also found at the Hayden Quarry are the remains of phytosaurs, aetosaurs, rauisuchians, and several types of dinosaurs and dinosaur relatives, including a Silesaurus-like animal, the herrerasaurid Chindesaurus, and the basal theropod Tawa. Finding the remains of four types of dinosaurs and dinosaur relatives (including Dromomeron itself) is noteworthy because it shows that dinosaurs did not immediately replace their dinosauromorph predecessors; that some of these groups, like the lagerpetonids, persisted (for longer than previously known) and diversified; and that dinosaurian replacement may have occurred at different times in different areas. References External links Online supplementary material for the Irmis et al.. article (PDF). A fact sheet for the Irmis et al.. article. Prehistoric avemetatarsalians Late Triassic archosaurs of North America Late Triassic reptiles of South America Fossil taxa described in 2007 Triassic Argentina Lagerpetidae