Therapsida is a major group of eupelycosaurian synapsids that includes mammals and their ancestors. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath the body, as opposed to the sprawling posture of many reptiles and salamanders. The earliest fossil attributed to Therapsida used to be Tetraceratops insignis from the Lower Permian. However in 2020, a new study has found that Tetraceratops is not actually a true Therapsid, but should be considered to be a member of the more ancient Sphenacodontia from which the therapsids evolved.
Eotitanosuchus is an extinct genus of biarmosuchian therapsids whose fossils were found in the town of Ochyor in Perm Krai, Russia. It lived about 267 million years ago. The only species is Eotitanosuchus olsoni.
Biarmosuchia is an extinct clade of non-mammalian synapsids from the Permian. Biarmosuchians are the most basal group of the therapsids. They were moderately-sized, lightly-built carnivores, intermediate in form between basal sphenacodont "pelycosaurs" and more advanced therapsids. Biarmosuchians were rare components of Permian ecosystems, and the majority of species belong to the clade Burnetiamorpha, which are characterized by elaborate cranial ornamentation.
Ericiolacerta is an extinct genus of small therocephalian therapsids from the early Triassic of South Africa and Antarctica. It was around 20 centimetres (7.9 in) in length, with long limbs and relatively small teeth. It probably ate insects and other small invertebrates.
Tetraceratops insignis is an extinct synapsid from the Early Permian of Texas. It was originally classified as an early and very primitive member of Therapsida, a clade that includes mammals and their close extinct relatives. However, it is now seen as a primitive non-therapsid sphenacodont rather than a genuine basal therapsid.
Titanosuchus ferox is an extinct species of dinocephalian therapsids that lived in the Middle Permian epoch in South Africa.
Phthinosuchus is an extinct genus of therapsids from the Middle Permian of Russia. Phthinosuchus is the sole member of the family Phthinosuchidae. Phthinosuchus may have been one of the most primitive therapsids, meaning that its ancestors may have branched off early from the main therapsid line.
Pristerognathus is an extinct genus of therocephalian, known from the late Middle Permian (Capitanian) of South Africa. It lends its name to the Pristerognathus Assemblage Zone of the Beaufort Group of South African geological strata. Pristerognathus was a medium-sized therocephalian with a 25 cm (9.8 in) skull and a total length up to 1.5 m.
Doliosauriscus is an extinct genus of dinocephalian therapsids that lived in Russia during the mid-Permian Period. It was a large carnivore, its skull measuring 53 centimeters long. Doliosauriscus probably reached a length up to 4 m (13 ft).
Archaeosyodon is an extinct genus of dinocephalian therapsids. It was medium-sized, reaching about 1.5–2 m (4–5 ft) in length.
Nikkasaurus is an extinct genus of therapsids.
Ivantosaurus is an extinct genus of therapsid that lived in Russia during the Wordian stage of the Permian period, named in honor of Ivan Antonovich Efremov. Some paleontologists have suggested that Ivantosaurus is a large species of Eotitanosuchus.
Cistecephaloides is an extinct genus of dicynodont therapsids of the Cistecephalus Assemblage Zone, Beaufort Group of South Africa.
Niaftasuchus is an extinct genus of therapsids. Only one species is recorded, Niaftasuchus zekkeli, from Nyafta, basin of the Mezen' River, Arkhangelsk Oblast, Russia. The family Niaftasuchidae was created by Ivankhenko in 1990, and initially attributed to the Tapinocephalia, essentially on the basis of the dentition; later it was regarded as Biarmosuchia, by share big orbits and fused vomers.
Oudenodon is an extinct genus of dicynodont. It was common throughout southern Africa during the Late Permian. Several species of Oudenodon are known. Both O. bainii, the type species, and O. grandis are known from South Africa. Specimens of O. luangwensis have been found from Zambia. One species, O. sakamenensis, is the only therapsid yet known from Madagascar. It is the type genus of the family Oudenodontidae, which includes members such as Tropidostoma.
Reiszia is an extinct genus of therapsids from European Russia belonging to the family Nikkasauridae.
Zorillodontops is an extinct genus of therocephalian therapsids from the Early Triassic of South Africa.
Venjukovia is an extinct genus of therapsids from the Middle Permian of Russia. Venjukovia is known from many partial skull remains and was a common animal from the Isheevo fauna in Russia. Venjukovia had a 12 centimetres (4.7 in) long skull.
Ulemica is an extinct genus of venjukoviid therapsids. It was a basal member of the suborder Anomodontia that existed during the Middle Permian in Russia. The type species, U. invisa, was assigned to the genus Venjukovia prior to being placed within its own genus in 1996. This small anomonodont is only known from a partial skull found in the Amanakskaya Formation.
Raranimus is an extinct genus of therapsids of the Middle Permian. It was described in 2009 from a partial skull found in 1998 from the Dashankou locality of the Xidagou Formation, outcropping in the Qilian Mountains of Gansu, China. The genus is the most basal known member of the clade Therapsida, to which the later Mammalia belong.
