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.
Pisanosaurus is an extinct genus of early dinosauriform, likely an ornithischian or silesaurid, from the Late Triassic of Argentina. It was a small, lightly built, ground-dwelling herbivore, that could grow up to an estimated 1 m (3.3 ft) long. Only one species, the type, Pisanosaurus mertii, is known, based on a single partial skeleton discovered in the Ischigualasto Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina. This part of the formation has been dated to the late Carnian, approximately 229 million years ago.
Hyperodapedon is an extinct genus of rhynchosaur reptiles which lived during Late Triassic period. Like other rhynchosaurs, it was an heavily built archosauromorph, distantly related to archosaurs such as crocodilians and dinosaurs. Hyperodapedon in particular was part of the subfamily Hyperodapedontinae, a specialized rhynchosaurian subgroup with broad skulls, beaked snouts, and crushing tooth plates on the roof of the mouth.
Proterosuchus is an extinct genus of archosauriform reptiles that lived during the Early Triassic. It contains three valid species: the type species P. fergusi and the referred species P. alexanderi and P. goweri. All three species lived in what is now South Africa. The genus was named in 1903 by the South African paleontologist Robert Broom. The genus Chasmatosaurus is a junior synonym of Proterosuchus.
Mesosuchus is an extinct genus of basal Rhynchosaur from early Middle Triassic deposits of Eastern Cape, South Africa. It is known from the holotype SAM 5882, a partial skeleton, and from the paratypes SAM 6046, SAM 6536, SAM 7416 and SAM 7701 from the Aliwal North Euparkeria site. Mesosuchus is quite small, spanning around 30 cm in length. Mesosuchus was discovered and named by David Meredith Seares Watson in 1912.
Rhynchosaurus is a genus of rhynchosaur that lived during the Middle Triassic period. It lived in Europe. It was related to the archosaurs, but not within that group. The type species of Rhynchosaurus is R. articeps. Michael Benton named two additional species, R. spenceri and R. brodiei, but they were subsequently renamed Fodonyx and Langeronyx respectively. Fossils of Rhynchosaurus have been found in the Tarporley Siltstone Formation and possibly the Sherwood Sandstone Group of the United Kingdom.
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.
Fodonyx is an extinct genus of rhynchosaur from the middle Triassic epoch of Devon in England. Its fossils were discovered in Otter Sandstone Formation and were first assigned to Rhynchosaurus spenceri. This species was reassigned to its own genus, Fodonyx the holotype of which is EXEMS 60/1985/292, that described by David W. E. Hone and Michael J. Benton in 2008. More recently, one skull was reassigned to the new genus Bentonyx. It is distinguished from other rhynchosaurs by a single autapomorphy, the ventral angling of the paraoccipital processes. In all other rhynchosaurs these processes angle dorsally or are horizontal. It is not known if this conferred any advantage to Fodonyx. Fodonyx was between 40 and 50 cm long.
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.
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.
Howesia is an extinct genus of basal rhynchosaur from early Middle Triassic deposits of Eastern Cape, South Africa. It is known from the holotype SAM 5884, a partial skeleton with palate and partial lower jaws and from two paratypes, SAM 5885 and SAM 5886. It was found in the Burgersdorp Formation of the middle deposits of the Beaufort Group and referred to Subzone B of the Cynognathus Assemblage Zone. It was first named by Robert Broom in 1905 and the type species is Howesia browni, named after Alfred Brown.
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.
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.
Prolacerta is a genus of archosauromorph from the lower Triassic of South Africa and Antarctica. The only known species is Prolacerta broomi. The generic name Prolacerta is derived from Latin meaning “before lizard” and its species name broomi is in commemoration of the famous paleontologist Robert Broom, who discovered and studied many of the fossils found in rocks of the Karoo Supergroup. When first discovered, Prolacerta was considered to be ancestral to modern lizards, scientifically known as lacertilians. However, a study by Gow (1975) instead found that it shared more similarities with the lineage that would lead to archosaurs such as crocodilians and dinosaurs. Prolacerta is considered by modern paleontologists to be among the closest relatives of the Archosauriformes.
Aenigmastropheus is an extinct genus of early archosauromorph reptiles known from the middle Late Permian Usili Formation of Songea District, southern Tanzania. It contains a single species, Aenigmastropheus parringtoni, known solely from UMZC T836, a partial postcranial skeleton of a mature individual. It was collected in 1933, and first described in 1956, as a "problematic reptile" due to its unique morphology. Therefore, a binomial name was erected for this specimen in 2014. Aenigmastropheus was probably fully terrestrial.
Noteosuchus is an extinct genus of basal rhynchosaur known from the earliest Triassic deposits of Eastern Cape Province, South Africa. It was first named by David Meredith Seares Watson in 1912 and the type species is Eosuchus colletti. The generic name Eosuchus is preoccupied by the generic name of Eosuchus lerichei Dollo, 1907, a gavialoid crocodilian known from northern France. Thus, an alternative generic name, Noteosuchus, was proposed by Robert Broom in 1925. The generic name erected by Broom (1925) is a compound, meaning "Not Eosuchus", while "Eosuchus" is derived from the name of Eos, the goddess of the dawn in Greek mythology, and suchus, Latinized from the Greek souchos, an Egyptian crocodile god, thus meaning "dawn crocodile". The specific name, colletti, honors Mr. Collett for the discovery of the holotype and only known specimen.
Eohyosaurus is an extinct genus of basal rhynchosaur known from the early Middle Triassic Burgersdorp Formation of Free State, South Africa. It contains a single species, Eohyosaurus wolvaardti.
Brasinorhynchus is an extinct genus of derived stenaulorhynchine known from the late Middle Triassic Santa Maria Formation of Rio Grande do Sul, Brazil. It contains a single species, Brasinorhynchus mariantensis.
