"Dromasaurs" are an artificial grouping of small anomodont therapsids from the Middle and Late Permian of South Africa. They represent either a paraphyletic grade or a polyphyletic grouping of small non-dicynodont basal anomodonts rather than a clade, and as such are considered an invalid group today. "Dromasaurs" were historically united by their superficially similar appearances that were unlike other known anomodonts. They are all small in size with slender limbs and long tails, and have short skulls with very large eye sockets. "Dromasauria" traditionally includes three genera, all from the Karoo Supergroup of South Africa: Galepus, Galechirus, and Galeops. These genera have sometimes been divided into two subgroups, the monotypic family Galeopidae and the Galechiridae for Galechiris and Galepus.
Dicynodon is a genus of dicynodont therapsid that flourished during the Upper Permian period. Like all dicynodonts, it was an herbivorous animal. This synapsid was toothless, except for prominent tusks, hence the name. It probably cropped vegetation with a horny beak, much like a tortoise, while the tusks may have been used for digging up roots and tubers.
Emydops is an extinct genus of dicynodont therapsids from the Middle Permian to Late Permian of what is now South Africa. The genus is generally small and herbivorous, sharing the dicynodont synapomorphy of bearing two tusks. In the following years, the genus grew to include fourteen species. Many of these species were erected on the basis of differences in the teeth and the positioning of the frontal and parietal bones. A 2008 study narrowed Emydops down to two species, E. arctatus and the newly described E. oweni.
Vivaxosaurus is a genus of dicynodont from Late Permian (Changhsingian) of Russia. It has been found at Sokolki on the Northern Dvina River near Kotlas in Arkhangelsk Oblast, Russia. It lived during the latest Permian, and was a contemporary of Inostrancevia, Scutosaurus and Dvinia. Like all members of the genus, this animal was toothless, except for prominent tusks, and probably cropped vegetation with a horny beak, like a tortoise.
Lystrosauridae is a family of dicynodont therapsids from the Permian and Triassic time periods. It includes two genera, Lystrosaurus and Kwazulusaurus. Kwazulusaurus includes a single species, K. shakai, from the Late Permian of South Africa and Lystrosaurus includes many species from the Late Permian and Early Triassic of South Africa, India, and Antarctica.
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.
Peramodon is an extinct genus of dicynodont therapsid from the Late Permian Scutosaurus karpinskii Zone of the Salarevo Formation of Russia. The type species, P. amalitzkii, was first named in 1926 as Dicynodon amalitzkii.
Keyseria is an extinct genus of dicynodont therapsid. The type species K. benjamini was first named in 1948 as Dicynodon benjamini.
Euptychognathus is an extinct genus of dicynodont therapsid. The type species E. bathyrhynchus was first named in 1942 as Dicynodon bathyrhynchus. Fossils of the genus have been recovered from the Usili Formation of the Ruhuhu Basin in Tanzania.
Basilodon is an extinct genus of dicynodont therapsid. The type species, Basilodon woodwardi was originally named in 1921 as Dicynodon woodwardi. Fossils have been found in the Cistecephalus Assemblage Zone and Dicynodon Assemblage Zone of the Balfour Formation of the Beaufort Group in South Africa.
Therochelonia is a group of dicynodont therapsids. The group was named by British paleontologist Harry Seeley in 1894 and fell into disuse in the following century. Therochelonia was redefined as a node-based clade in 2009. It is defined as the last common ancestor of Cistecephalus microrhinus and Dicynodon lacerticeps, and all of its descendants. Below is a simplified cladogram from Kammerer et al. (2011) showing the phylogenetic placement of Therochelonia:
Sintocephalus is an extinct genus of dicynodont therapsid from the Late Permian of South Africa. Fossils are known from the Cistecephalus Assemblage Zone of the Beaufort Group. The type species of Sintocephalus, S. alticeps, was first named in 1913 as a species of Dicynodon. The genus was erected in 1934, but in subsequent years its species were often regarded as members of other dicynodont genera.
Gordonia is an extinct genus of dicynodont therapsid from the Late Permian of Scotland. Fossils have been found from the Elgin sandstone of Cutties Hillock Sandstone in Elgin, Moray. These are among the many amniote fossils referred to as the Elgin Reptiles. Gordonia was named in 1893 with four species: G. traquairi, G. duffiana, G. huxleyana, and G. juddiana. Currently, the only recognized species is the type G. traquairi. All other species are considered synonyms of the type.
Bidentalia is a group of dicynodont therapsids. Bidentalia was one of the first names used to describe dicynodonts; the group was established in 1876, while the name "bidentals" dates back as far as 1845. With the increasing prominence of phylogenetics, the group was redefined as a clade in 2009. Bidentalia is now considered a stem-based taxon that includes all taxa more closely related to Aulacephalodon bainii and Dicynodon lacerticeps than Emydops arctatus.
Daqingshanodon is an extinct genus of dicynodont therapsid from the Late Permian of Inner Mongolia, China. The type species D. limbus was described in 1989 from a single skull found in the Naobaogou Formation. Daqingshanodon belongs to a group of dicynodonts called cryptodonts. It is the smallest known cryptodont, and the only one known from China. Like other cryptodonts, it has a pair of rounded nasal bosses above its nostrils and a ridge of bone on the upper jaw called the postcaniniform process. Daqingshanodon has a pair of elongated, recurved tusks extending from its beak-like snout. It is distinguished from other dicynodonts by the presence of a distinct ridge running along the side of the skull from below the eye socket to the area around the tusks. The skull of Daqingshanodon is less than 10 centimetres (3.9 in) long, yet this specimen is thought to have been an adult on the basis of its well-developed nasal bosses.
Kistecephalia is a clade of dicynodont therapsids. The group was first named in 1894, and was reinstated as a clade in 2009. Kistecephalia is a stem-based taxon defined as all taxa more closely related to Cistecephalus microrhinus than Emydops arctatus. It includes the families Myosauridae, Kingoriidae, and Cistecephalidae and is part of the larger group Emydopoidea. Kistecephalians were small in comparison to other dicynodonts. One group of kistecephalians, the cistecephalids, are thought to have been burrowers. Below is a cladogram from Kammerer et al. (2011) showing the phylogenetic relationships of kistecephalians:
Jimusaria is an extinct genus of dicynodont therapsid from the Late Permian (Changhsingian) of China. The type species J. sinkianensis from the Guodikeng Formation in Xinjiang, was originally named as a species of Dicynodon, the first from Asia, but was given its own genus in 1963 before being sunk back into Dicynodon in 1988. The genus was resurrected in 2011 by palaeontologist Christian Kammerer in a taxonomic revision of the genus Dicynodon. Jimusaria was a mid-sized dicynodont, and was similar in appearance to the South African Dicynodon, but differed from it in features such as its narrower snout. A second species, Jimusaria monanensis was described from the Naobaogou Formation of northern China in 2023.
Turfanodon is an extinct genus of dicynodont therapsid from the Late Permian Sunan, Guodikeng, and Naobaogou Formations of China. The holotype of T. bogdaensis was discovered between 1963-1964 and was originally named in 1973 by A. Sun with the type species Turfanodon bogdaensis, Turfanodon was reclassified as a junior synonym of the related Dicynodon in 1988 by G. M. King. T. bogdaensis remained a species of Dicynodon for over two decades before the genus was reinstated in 2011 in a revision of the taxonomy of Dicynodon by palaeontologist Christian Kammerer. A second species from Inner Mongolia, T. jiufengensis, was named in 2021 by palaeontologist Jun Liu from a nearly complete skeleton and other referred bones. Turfanodon was a relatively large dicynodont, and similar in appearance to the related Daptocephalus from South Africa.
Kunpania is an extinct genus of dicynodont therapsid from the Quanzijie Formation of Xinjiang, China. The type and only species is K. scopulusa, and it is known only by a single incomplete specimen including parts of the skull and forelimb. Since its initial description in 1978 by palaeontologist Ailing Sun, it has sometimes been considered to be another species of Dicynodon by other researchers, or potentially undiagnostic. However, a redescription in 2021 reaffirmed its distinctiveness, including a uniquely well developed muscle attachment on the humerus. Kunpania is perhaps the oldest known member of the derived dicynodont group Dicynodontoidea, potentially dating to the Middle Permian period during the Capitanian, and so may fill a knowledge gap in the history of dicynodont evolution.
Bulbasaurus is an extinct genus of dicynodont that is known from the Lopingian epoch of the Late Permian period of what is now South Africa, containing the type and only species B. phylloxyron. It was formerly considered as belonging to Tropidostoma; however, due to numerous differences from Tropidostoma in terms of skull morphology and size, it has been reclassified the earliest known member of the family Geikiidae, and the only member of the group known from the Tropidostoma Assemblage Zone. Within the Geikiidae, it has been placed close to Aulacephalodon, although a more basal position is not implausible.
