Rhynchosaurs are a group of extinct herbivorous Triassic archosauromorph reptiles, belonging to the order Rhynchosauria. Members of the group are distinguished by their triangular skulls and elongated, beak like premaxillary bones. Rhynchosaurs first appeared in the Early Triassic, reaching their broadest abundance and a global distribution during the Carnian stage of the Late Triassic.
Prestosuchus is an extinct genus of pseudosuchian in the group Loricata, which also includes Saurosuchus and Postosuchus. It has historically been referred to as a "rauisuchian", and was the defining member of the family Prestosuchidae, though the validity of both of these groups is questionable: Rauisuchia is now considered paraphyletic and Prestosuchidae is polyphyletic in its widest form.
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age, and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and other dinosauromorphs, including the herrerasaurid Staurikosaurus, the basal sauropodomorphs Buriolestes and Saturnalia, and the lagerpetid Ixalerpeton. The formation is named after the city of Santa Maria in the central region of Rio Grande do Sul, where outcrops were first studied.
The Caturrita Formation is a rock formation found in Rio Grande do Sul, Brazil. Its sediments were deposited in the Paraná Basin. The formation is from the Upper Triassic and forms part of the Santa Maria Supersequence in the upper section of the Rosário do Sul Group.
Proterochampsa is an extinct genus of proterochampsid archosauriform from the Late Triassic of South America. The genus is the namesake of the family Proterochampsidae, and the broader clade Proterochampsia. Like other proterochampsids, Proterochampsa are quadruped tetrapods superficially similar in appearance to modern crocodiles, although the two groups are not closely related. Proterochampsids can be distinguished from other related archosauriformes by characters such as a dorsoventrally flattened, triangular skull with a long, narrow snout at the anterior end and that expands transversally at the posterior end, asymmetric feet, and a lack of postfrontal bones in the skull, with the nares located near the midline. Proterochampsa is additionally defined by characters of dermal sculpturing consisting of nodular protuberances on the skull, antorbital fenestrae facing dorsally, and a restricted antorbital fossa on the maxilla. The genus comprises two known species: Proterochampsa barrionuevoi and Proterochampsa nodosa. P. barrionuevoi specimens have been discovered in the Ischigualasto Formation in northwestern Argentina, while P. nodosa specimens have been found in the Santa Maria supersequence in southeastern Brazil. The two species are distinct in several characters, including that P. nodosa has larger, more well-developed nodular protuberances, a more gradually narrowing snout, and a higher occiput than P. barrionuevoi. Of the two, P. nodosa is thought to have less derived features than P. barrionuevoi.
Trucidocynodon is an extinct genus of ecteniniid cynodonts from the Upper Triassic (Carnian) of Brazil. It contains a single species, Trucidocynodon riograndensis. Fossils of Trucidocynodon were discovered in outcrops of the Upper Santa Maria Formation in Paleorrota Geopark Agudo. Trucidocynodon is one of the most completely known Triassic cynodonts, as its holotype is a nearly complete and fully articulated skeleton.
Isalorhynchus is an extinct genus of hyperodapedontine rhynchosaur from the late Triassic period of Toliara Province, southwestern Madagascar. It is known from the holotype MDE-R18, a nearly complete maxilla and from other specimens from the same locality, Malio River area. It was found in the Makay Formation of the Morondava Basin. It was first named by Eric Buffetaut in 1983 and the type species is Isalorhynchus genovefae. The majority of Isalorhynchus specimens are isolated jaw bones, but two nearly complete skeletons were found in 1998. Langer et al., 2000 concluded that Isalorhynchus is a synonym of Hyperodapedon and referred it to a new species of Hyperodapedon. Whatley, 2005 retained this genus as valid with a description of new materials in her PhD thesis. Montefeltro et al., 2010 and Langer et al., 2010 accepted Isalorhynchus as valid genus.
Bentonyx is an extinct genus of rhynchosaur from the middle Triassic epoch of Devon in England. Its fossil, a well preserved skull, BRSUG 27200, was discovered in Otter Sandstone Formation and was first assigned to Rhynchosaurus spenceri, that is known from 25 specimens. This species was reassigned to its own genus, Fodonyx, that was first described by David W. E. Hone and Michael Benton in 2008. More recently, this skull was reassigned to this genus by Max C. Langer, Felipe C. Montefeltro, David E. Hone, Robin Whatley and Cesar L. Schultz in 2010 and the type species is Bentonyx sidensis.
Teyumbaita is an extinct genus of hyperodapedontine rhynchosaur from the Upper Triassic of southern Brazil. Its fossils were recovered from the early Norian-age Caturrita Formation, one of several fossiliferous formations exposed at Paleorrota Geopark in the state of Rio Grande do Sul. Teyumbaita is likely the youngest valid genus of rhynchosaur, as other members of the group likely died out before the start of the Norian.
Sangaia is an extinct genus of rhytidosteid temnospondyl from the early Triassic period of Rio Grande do Sul, Brazil. It is known from the holotype UMVT 4302, the left half of a partial skull, a partial palate, from the paratype UMVT 4303, a partial right palatal fragment and from the referred specimens PV 0497 T and MCN PV 2606, skull fragments, recovered from the Sanga do Cabral Formation in the Rośario do Sul Group.
Stenaulorhynchus is an extinct genus of hyperodapedontid rhynchosaur known from the Middle Triassic deposits of Tanganyika Territory, Tanzania. It was found in the Lifua Member of the Manda Formation in the Karoo Supergroup. It was named and first described by Sidney Henry Haughton in 1932. The type species is Stenaulorhynchus stockleyi, a beaked herbivore measuring 1–6 meters in length.
Supradapedon is an extinct genus of hyperodapedontine rhynchosaur from mid-late Triassic deposits of Tanganyika Territory, Tanzania. It is known from the holotype SAM-11704. The holotype and only specimen of Supradapedon was first assigned to a species of Scaphonyx, Scaphonyx stockleyi. This species was reassigned to its own genus by Sankar Chatterjee in 1980 and the type species is Supradapedon stockleyi. One study, Langer et al. (2000), concluded that Supradapedon is a synonym of Hyperodapedon and referred it to Hyperodapedon sp. However, the provisional validity of this genus has been commonly accepted since.
Hyperodapedontinae is a subfamily of rhynchosaurs within the family Rhynchosauridae. Fossils have been found from Argentina, Brazil, Canada, India, Madagascar, Scotland, Tanzania, United States and Zimbabwe.
Macrocephalosaurus is a genus of rhynchosaurs from the Late Triassic period of southern Brazil. Although usually synonymized with Hyperodapedon, recent cladistic analysis has called this synonymy into question.
Otischalkia is an extinct genus of archosauromoph from late Triassic deposits of Howard County, Texas, US It is known from the holotype TMM 31025-263, left humerus and from the referred specimens TMM 31025-262, TMM 31025-266, TMM 31025-264, TMM 31185-92 and TMM 31185-93. It was found in the Lower Dockum Group near the abandoned settlement of Otis Chalk. It was first named by Adrian P. Hunt and Spencer G. Lucas in 1991 and the type species is Otischalkia elderae.
Candelariodon is an extinct genus of carnivorous probainognathian cynodonts from the Middle to Late Triassic Santa Maria Formation of the Paraná Basin in Rio Grande do Sul state, Brazil. Candelariodon is known from a partial mandible having some complete teeth. It was first named by Téo Veiga de Oliveira, Cesar Leandro Schultz, Marina Bento Soares and Carlos Nunes Rodrigues in 2011 and the type species is Candelariodon barberenai.
Epipophyses are bony projections of the cervical vertebrae found in archosauromorphs, particularly dinosaurs. These paired processes sit above the postzygapophyses on the rear of the vertebral neural arch. Their morphology is variable and ranges from small, simple, hill-like elevations to large, complex, winglike projections. Epipophyses provided large attachment areas for several neck muscles; large epipophyses are therefore indicative of a strong neck musculature.
Langeronyx is an extinct genus of basal rhynchosaurid known from the early Middle Triassic Bromsgrove Sandstone Formation of Warwickshire, UK. It contains a single species, Langeronyx brodiei, originally included in the genus Rhynchosaurus. R. brodiei was first described and named by Michael Benton in 1990, but its redescription by Martín D. Ezcurra, Felipe Montefeltro and Richard J. Butler in 2016 recovered it as more closely related to the more advance hyperodapedontine than to the type species of Rhynchosaurus and thus it was moved to its own genus. The generic name Langeronyx honors the Brazilian paleontologist Max Cardoso Langer in recognition of his rhynchosaur research, combined with the Greek onyx (óνυξ) meaning "claw", a common suffix for rhynchosaur genera. L. brodiei is known solely from the holotype, a partial skull divided into the two specimens WARMS G6097/1 and NHMUK PV R8495, housed in the Warwickshire Museum, Warwick and Natural History Museum, London, respectively. Other specimens originally referred to R. brodiei either do not overlap with its type or can be just as likely referred to other basal rhynchosaurids. L. brodiei is one of two basal archosauromorphs known from the Bromsgrove Sandstone Formation, the other being the lesser known Rhombopholis scutulata.
Bagualosaurus is a genus of sauropodomorph dinosaur from the Candelária Sequence of Brazil, dating to around 230 million years ago in the Carnian of the Late Triassic. It includes one species, Bagualosaurus agudoensis.
Bonacynodon is an extinct genus of cynodonts that lived in what is now southern Brazil during the Triassic period. The genus is monotypic, containing only the type species Bonacynodon schultzi. B. schultzi is known from two specimens, consisting of two partial skulls and some badly preserved parts of the postcranium. Both specimens were recovered from the Pinheiros-Chiniquá Sequence, part of the Santa Maria Supersequence of the Paraná Basin. This sequence preserves a faunal association known as the Dinodontosaurus Assemblage Zone, which contains numerous other species of cynodonts, dicynodonts and reptiles. Bonacynodon was a small, likely insectivorous cynodont, whose length has been estimated at around 30 centimetres (12 in). It can be distinguished from other cynodonts by its large, serrated (saw-like) canine teeth. Together with the genus Probainognathus of Argentina, it made up the family Probainognathidae, one of the earliest-diverging lineages of the clade Probainognathia. It was a fairly close relative of mammals, the only group of cynodonts alive today.
