In 1928 or 1929, near the road from
Santa Maria to
San Jose, Dr. Wilhelm Rau, a German fossil collector working under
Friedrich von Huene, discovered the remains of a
rauisuchid crocodile. The Zahnsanga site was part of the Alemoa Member of the
Santa Maria Formation and was found in the uppermost of an layer. von Huene then sent the
R. tiradentes material back to Germany alongside other fossils, including the holotype of
Prestosuchus chiniquensis. but no diagnosis or description was given, so it remained a
nomen dubium until being properly described by von Huene (1942). 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). 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. ==Description==