Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first appeared in Southern Pangaea during the mid-Permian, ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the Late Permian, ca. 260–252 Mya. They were devastated by the end-Permian Extinction that wiped out most other therapsids ca. 252 Mya. They rebounded during the Triassic but died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat-sized burrowers to elephant-sized browsers.
Anomodontia is an extinct group of non-mammalian therapsids from the Permian and Triassic periods. By far the most speciose group are the dicynodonts, a clade of beaked, tusked herbivores. Anomodonts were very diverse during the Middle Permian, including primitive forms like Anomocephalus and Patranomodon and groups like Venyukovioidea and Dromasauria. Dicynodonts became the most successful and abundant of all herbivores in the Late Permian, filling ecological niches ranging from large browsers down to small burrowers. Few dicynodont families survived the Permian–Triassic extinction event, but one lineage (Kannemeyeriiformes) evolved into large, stocky forms that became dominant terrestrial herbivores right until the Late Triassic, when changing conditions caused them to decline, finally going extinct during the Triassic–Jurassic extinction event.
Robertia is an extinct genus of small herbivorous dicynodonts from the Middle to Late Permian of South Africa, between 260 and 265 million years ago. It is a monospecific genus, consisting of the type-species R. broomiana, which was classified by Lieuwe Dirk Boonstra in 1948 and named in honor of Robert Broom for his study of South African mammal-like reptiles.
The Tapinocephalus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 2,000 metres (6,600 ft), occur from Merweville and Leeu-Gamka in its southernmost exposures, from Sutherland through to Beaufort West where outcrops start to only be found in the south-east, north of Oudshoorn and Willowmore, reaching up to areas south of Graaff-Reinet. Its northernmost exposures occur around the towns Fraserburg and Victoria West. The Tapinocephalus Assemblage Zone is the second biozone of the Beaufort Group.
The Eodicynodon Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 620 metres (2,030 ft), occur south-east of Sutherland, north of Prince Albert, and south-east of Beaufort West. The Eodicynodon Assemblage Zone is the lowermost biozone of the Beaufort Group.
Tapinocaninus is an extinct genus of therapsids in the family Tapinocephalidae, of which it is the most basal member. Only one species is known, Tapinocaninus pamelae. The species is named in honor of Rubidge's mother, Pam. Fossils have been found dating from the Middle Permian.
Anomocephalus is an extinct genus of primitive anomodonts and belongs to the clade Anomocephaloidea. The name is said to be derived from the Greek word anomos meaning lawless and cephalos meaning head. The proper word for head in Greek is however κεφαλή (kephalē). It is primitive in that it retains a complete set of teeth in both jaws, in contrast to its descendants, the dicynodonts, whose dentition is reduced to only a single pair of tusks, with their jaws covered by a horny beak similar to that of a modern tortoise. However, they are in no way closely related.
Patranomodon is an extinct genus belonging to the group of Anomodontia. Rubidge and Hopson named this anomodont in 1990 after discovering its skull. Patranomodon is known to have ranged in the Karoo of Southern Africa.
Venyukovia is an extinct genus of venyukovioid therapsid, a basal anomodont from the Middle Permian of Russia. The type and sole species, V. prima, is known only by a partial lower jaw with teeth. Venyukovia has often been incorrectly spelt as 'Venjukovia' in English literature. This stems from a spelling error made by Russian palaeontologist Ivan Efremov in 1940, who mistakenly replaced the 'y' with a 'j', which subsequently permeated through therapsid literature before the mistake was caught and corrected. Venyukovia is the namesake for the Venyukovioidea, a group of small Russian basal anomodonts also including the closely related Otsheria, Suminia, Parasuminia and Ulemica, although it itself is also one of the poorest known. Like other venyukovioids, it had large projecting incisor-like teeth at the front and lacked canines, although the remaining teeth are simple compared to some other venyukovioids, but may resemble those of Otsheria.
Myosaurus is a genus of Anomodontia in the order Therapsida. They are also classified as Dicynodontia, which is a subclade of Anomodontia. The Mysosaurus was a small, herbivorous synapsid that existed around the early Triassic period. All of the fossils found of this species were found in Antarctica and South Africa. Compared to other fossils found from species that existed during this time, the Myosaurus is not common in the fossil record. This is due to a shortage of discovered fossils that possess characteristics unique to the Myosaurus. Notably, under 130 fossil fragments have been found that have been classified as Myosauridae, and almost all have been skulls. These skulls can be classified as Myosaurus because this species, unlike other dicynodonts, do not possess tusks or postfrontal teeth. The only species identified in the family Myosauridae is the Myosaurus gracilis, or M. gracilis. It should be recognized that the Myosaurus is almost always referred to as the M. gracilis in scientific research.
Brachyprosopus is an extinct genus of dicynodont therapsid from the middle Permian Tapinocephalus Assemblage Zone in the Abrahamskraal Formation belonging to the Beaufort Group of the Karoo Basin, South Africa.
Dimacrodon is an extinct genus of non-mammalian synapsid from the latest Early Permian San Angelo Formation of Texas. It is distinguished by toothless, possibly beaked jaw tips, large lower canines and a thin bony crest on top of its head. Previously thought to be an anomodont therapsid related to dicynodonts, it was later found to lack any diagnostic features of anomodonts or even therapsids and instead appears to be a 'pelycosaur'-grade synapsid of uncertain classification.
Kawingasaurus is an extinct genus of dicynodont therapsid from the Late Permian Usili Formation of Tanzania. It is a member of the family Cistecephalidae, and like other cistecephalids it is thought to have been fossorial. It is a member of the family Cistecephalidae. Cistephalidae includes genera Cisteceohalus, Cistecephaloides and Kawingasaurus. Greek for Saurus meaning “lizard” appears as a suffix denoting a reptilian origin. Living between 254.17 and 259.9 million years ago in the late Permian and believed to have the first and last recorded appearance in this time period. It lived in deep burrows as a suggested by most burrowing dicynodonts from evaluation of cranial sutures, vestibule inflation and enlarged stapes foot plates which are thought to be functionally correlated with bone-conduction hearing; all observed in fossorial vertebrates which use seismic signals as communication.
Ulemica is an extinct genus of venyukovioid therapsids, a type of anomodont related to dicynodonts. It lived during the Middle Permian period in what is now Russia, and is known from the Isheevo assemblage of the Amanakskaya Formation. The type species, U. invisa, was originally placed in the genus Venyukovia by Russian palaeontologist Ivan Efremov in 1940. It was later given its own genus Ulemica in 1996 by Mikhaïl Ivakhnenko, who also named a second species U. efremovi. Efremov had originally intended to name the fossils of U. invisa as 'Myctosuchus invisus', however, he later recognised their similarity to Venyukovia and chose to assign the Isheevo material to this genus and leaving 'Myctosuchus' a nomen nudum.
Venyukovioidea is an infraorder of anomodont therapsids related to dicynodonts from the Permian of Russia. They have also been known as 'Venjukovioidea', as well as by the similar names 'Venyukoviamorpha' or 'Venjukoviamorpha' in literature. This in part owes to a misspelling by Russian palaeontologist Ivan Efremov in 1940 when he mistakenly spelt Venyukovia, the namesake of the group, with a 'j' instead of a 'y', which permeated through subsequent therapsid literature before the mistake was caught and corrected. The order Ulemicia has also been coined for a similar taxonomic concept in Russian scientific literature, which notably excludes Suminia and Parasuminia.
Chainosauria is a large and speciose clade of anomodont therapsid that includes the highly diverse dicynodonts and a small number of closely related basal genera —although the total composition and taxonomic scope of Chainosauria is in flux. Chainosauria was named in 1923 to group together the dicynodonts and their close relatives, namely three small anomodont genera from South Africa that made up the now defunct group 'Dromasauria'. The name soon fell into disuse, however, as it was functionally replaced by Anomodontia. Chainosauria was later revived cladistically in 2009, preserving the association of dicynodonts and the 'dromasaurs' and has since served in effect as both a cladistic and a biogeographic counterpart to the Laurasian venyukovioids, with early chainosaurs appearing to have been a Gondwanan radiation.
Pylaecephalidae is a family of dicynodont therapsids that includes Diictodon, Robertia, and Prosictodon from the Permian of South Africa. Pylaecephalids were small burrowing dicynodonts with long tusks. The family was first named in 1934 and was redefined in 2009. Diictodontidae and Robertiidae are considered junior synonyms of Pylaecephalidae; although Pylaecephalus itself is considered a junior synonym of Diictodon, the name Pylaecephalidae predates these names and therefore takes priority.
The Abrahamskraal Formation is a geological formation and is found in numerous localities in the Northern Cape, Western Cape, and the Eastern Cape of South Africa. It is the lowermost formation of the Adelaide Subgroup of the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup. It represents the first fully terrestrial geological deposits of the Karoo Basin. Outcrops of the Abrahamskraal Formation are found from the small town Middelpos in its westernmost localities, then around Sutherland, the Moordenaarskaroo north of Laingsburg, Williston, Fraserburg, Leeu-Gamka, Loxton, and Victoria West in the Western Cape and Northern Cape. In the Eastern Cape outcrops are known from Rietbron, north of Klipplaat and Grahamstown, and also southwest of East London.
Anomocephaloidea is a clade of basal anomodont therapsids related to the dicynodonts known from what is now South Africa and Brazil during the Middle Permian. It includes only two species, Anomocephalus africanus from the Karoo Basin of South Africa and Tiarajudens eccentricus from the Paraná Basin of Brazil. Anomocephaloidea was named in 2011 with the discovery of Tiarajudens, although Anomocephalus itself has been known since 1999.
Thliptosaurus is an extinct genus of small kingoriid dicynodont from the latest Permian period of the Karoo Basin in KwaZulu-Natal, South Africa. It contains the type and only known species T. imperforatus. Thliptosaurus is from the upper Daptocephalus Assemblage Zone, making it one of the youngest Permian dicynodonts known, living just prior to the Permian mass extinction. It also represents one of the few small bodied dicynodonts to exist at this time, when most other dicynodonts had large body sizes and many small dicynodonts had gone extinct. The unexpected discovery of Thliptosaurus in a region of the Karoo outside of the historically sampled localities suggests that it may have been part of an endemic local fauna not found in these historic sites. Such under-sampled localities may contain 'hidden diversities' of Permian faunas that are unknown from traditional samples. Thliptosaurus is also unusual for dicynodonts as it lacks a pineal foramen, suggesting that it played a much less important role in thermoregulation than it did for other dicynodonts.
