A Revueltosaur-like Tooth from the Petrified Forest Formation (upper Triassic: Revueltian), Zion National Park

We describe an isolated archosauriform tooth from the Upper Triassic Painted Desert Member of the Petrified Forest Formation in Zion National Park in southwestern Utah. This tooth is relatively low (mesiodistally as long as baso-apically tall), bulbous and asymmetrical in occlusal view, and has denticles that are oblique to the tooth crown. The base of the tooth is also slightly expanded relative to the root. Among Triassic archosaurs, this tooth most closely resembles maxillary/dentary teeth of Revueltosaurus callenderi Hunt, although the Utah specimen is somewhat smaller and bears finer denticles than typical R. callenderi teeth. Although most archosaurs have somewhat generalized teeth, there are distinctive morphotypes, and these have been shown to reliably document taxa that are rarer than the usual phytosaurs, aetosaurs, and metoposaurs the dominate most Chinle