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Rauisuchus (meaning "Wilhelm Rau's crocodile") is a genus of extinct which lived in what is now the Geopark of Paleorrota (Santa María Formation), Brazil, during the Triassic period (235–228 million years ago). It contains one species, R. tiradentes. Rauisuchus at Fossilworks.orgF. v. Huene. (1942) Die fossilen Reptilien des südamerikanischen Gondwanalandes. Ergebnisse der Sauriergrabung in Südbrasilien 1928/29. München: C.H. Beck'sche Verlagsbuchhandlung
von Huene (1936) named Rauisuchus in a list of the Thecodontia,v. Huene, F. (1936). The constitution of the Thecodontia. American Journal of Science 32:207-217 but no diagnosis or description was given, so it remained a nomen dubium until being properly described by von Huene (1942).
Krebs (1973) described the tarsus of R. tiradentesKrebs, B. (1973). Der Tarsus von Rauisuchus (Pseudosuchia, MIttel-Trias). Mitteilungen der Bayerischen Staatssammlung für Paläontologie und historische Geologie 13: 95–101. and the lectotype was assigned in 1976 and consists of BSPG AS XXV 60–68, 71–100, 105–119 and 121 (the right premaxilla, right postorbital, left squamosal, left jugal, right pterygoid, right nasal, both splenials, left surangular, prearticular and angular, odontoid(?), axis, cervical, dorsal and caudal vertebrae, ribs, chevron bones, right scapulacoracoid, left pubis, right tibia, fibula and astragalus, and body osteoderms).Krebs, B. (1976). Pseudosuchia. In: Kuhn O, ed Handbuch der Paläoherpetologie, Thecodontia. Stuttgart: Gustav Fischer Verlag, 40–98. It is unclear if the lectotype remains belonged to one or two individuals.
The specimens found by Rau were eventually re-described by Lautenschlager & Rauhut (2014) and they identified that from Localities 15-17, one or two specimens were found. According to von Huene (1942), 'Find 1025' was assigned to BSPG AS XXV 122 (a partial left maxilla) and 'Find 1020' was assigned to BSPG AS XXV 123 (a cervical vertebra), BSPG AS XXV 124, (a rib fragment), BSPG AS XXV 120 and BSPG, no number (two chevron bone fragments) and BSPG AS XXV 88 (a complete left ilium). Lautenschlager & Rauhut (2014) found that the remains from Locality 15 ('Find 1020') could not be diagnostically assigned to Rauisuchus, and so were removed from the genus. They also noted that von Huene (1942) assigned two more specimens from other localities to R. tiradentes: several isolated teeth, BSPG AS XXV 101 (the proximal end of an ulna) and BSPG AS XXV 102 (a partial metatarsal), but these cannot be confidently assigned to R. tiradentes as no overlapping material is known.
Rauisuchus is distinguished from other members of the Rauisuchidae on the basis of a knob-like thickening on the base of the posterior process of the premaxilla, short, ventrally keeled cervicals, lacking postzygodiapophyseal laminae, and elongated caudals with an accessory neural spine and a postspinal lamina.
It was placed as the Sister group to Tikisuchus and Yarasuchus, forming a clade with the two.
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