Pravusuchus is an extinct genus of leptosuchomorph parasuchid phytosaur known from the Late Triassic (Norian stage) of Arizona, United States. It contains a single species, Pravusuchus hortus, which is known from three specimens. These specimens were previously referred to Smilosuchus or to Leptosuchus, but Pravusuchus's autapomorphy, its phylogenetic position as well as a trait shared with mystriosuchins, justified the erection of a new taxon for the material.[1]
Pravusuchus was first described and named by Michelle R. Stocker in 2010 and the type species is Pravusuchus hortus. The generic name is derived from Latin, pravus, "evil" or "wicked", and Greek, souchus, for the Egyptian crocodile-headed god Sobek. The specific name, hortus, is the Latin word for park or grounds. The name refers to Devil's Playground, the locality in Petrified Forest National Park from which all specimens of this taxon were collected. Pravusuchus is known from the holotype AMNH FR 30646, mostly complete but partially disarticulated skull, and from the referred specimens PEFO 31218, a partial skull, and PEFO 34239, partial skull, partial mandible, and possible partial postcrania. Although the holotype is slightly crushed dorsoventrally, it is not as flattened as PEFO 31218. All specimens referable to Pravusuchus were collected from the Sonsela Sandstone Bed (later referred to as Jasper / Rainbow Forest Bed[2]) of the Norian-aged Sonsela Member, Chinle Formation from Navajo County, Arizona. PEFO 31218 and PEFO 34239 were found in the same stratigraphic horizon just west of Colbert's 1946 locality where AMNH FR 30646 was collected, and only 2–3 m higher stratigraphically than the holotype.[1] Other phytosaur specimens from the Sonsela Member occur in other beds, stratigraphically lower (e.g. Protome batalaria, Smilosuchus adamanensis[1] and S. lithodendrorum) or higher (e.g. Machaeroprosopus jablonskiae and M. pristinus) then the white Rainbow Forest sandstone.[2]
Stocker (2010) diagnosed Pravusuchus hortus by a single unambiguous autapomorphy (unique trait) and additionally by a unique combination of characters. Unlike all other phytosaurs, the lateral rim of its external naris (i.e. nostril) is formed by the "septomaxilla", and not by the nasal bone. The element in phytosaur skulls anterior to the external nares, located between the nasal, maxilla and premaxilla, has traditionally been referred to as the septomaxilla, however it probably is not homologous to the septomaxillae of squamates and synapsids.[1]