A therapsid is a member of the clade Therapsida which is a major group of eupelycosaurian synapsids that includes mammals and their ancestors and relatives. 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.
Cynodonts are eutheriodont therapsids that first appeared in the Late Permian, and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ancestors and close relatives (Mammaliaformes), having evolved from advanced probainognathian cynodonts during the Late Triassic.
Moschops is an extinct genus of therapsids that lived in the Guadalupian epoch, around 265–260 million years ago. They were heavily built plant eaters, and they may have lived partly in water, as hippopotamuses do. They had short, thick heads and might have competed by head-butting each other. Their elbow joints allowed them to walk with a more mammal-like gait rather than crawling. Their remains were found in the Karoo region of South Africa, belonging to the Tapinocephalus Assemblage Zone. Therapsids, such as Moschops, are synapsids, the dominant land animals in the Permian period, which ended 252 million years ago.
Gorgonopsia is an extinct clade of sabre-toothed therapsids from the Middle to Upper Permian roughly 265 to 252 million years ago. They are characterised by a long and narrow skull, as well as elongated upper and sometimes lower canine teeth and incisors which were likely used as slashing and stabbing weapons. Postcanine teeth are generally reduced or absent. For hunting large prey, they possibly used a bite-and-retreat tactic, ambushing and taking a debilitating bite out of the target, and following it at a safe distance before its injuries exhausted it, whereupon the gorgonopsian would grapple the animal and deliver a killing bite. They would have had an exorbitant gape, possibly in excess of 90°, without having to unhinge the jaw.
Gorgonops is an extinct genus of gorgonopsian therapsid, of which it is the type genus. Gorgonops lived during the Late Permian (Wuchiapingian), about 260–254 million years ago in what is now South Africa.
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.
Dinogorgon is a genus of gorgonopsid from the Late Permian of South Africa and Tanzania. The generic name Dinogorgon is derived from Greek, meaning "terrible gorgon", while its species name rubidgei is taken from the surname of renowned Karoo paleontologist, Professor Bruce Rubidge, who has contributed to much of the research conducted on therapsids of the Karoo Basin. The type species of the genus is D. rubidgei.
Anteosaurus is an extinct genus of large carnivorous dinocephalian synapsid. It lived at the end of the Guadalupian during the Capitanian stage, about 265 to 260 million years ago in what is now South Africa. It is mainly known by cranial remains and few postcranial bones. Measuring 5–6 m (16–20 ft) long and weighing about 600 kg (1,300 lb), Anteosaurus was the largest known carnivorous non-mammalian synapsid and the largest terrestrial predator of the Permian period. Occupying the top of the food chain in the Middle Permian, its skull, jaws and teeth show adaptations to capture large prey like the giants titanosuchids and tapinocephalids dinocephalians and large pareiasaurs.
Trochosaurus is a dubious genus of therocephalian therapsid from South Africa based upon specimens of Lycosuchidae. Three species of Trochosaurus have appeared in literature, T. intermedius, T. major, and T. dirus. The genus Trochosaurus and all three species are considered nomen dubia today, while the specimens referred to them are regarded as Lycosuchidae incertae sedis.
Euchambersia is an extinct genus of therocephalian therapsids that lived during the Late Permian in what is now South Africa and China. The genus contains two species. The type species E. mirabilis was named by paleontologist Robert Broom in 1931 from a skull missing the lower jaw. A second skull, belonging to a probably immature individual, was later described. In 2022, a second species, E. liuyudongi, was named by Jun Liu and Fernando Abdala from a well-preserved skull. It is a member of the family Akidnognathidae, which historically has also been referred by as the synonymous Euchambersiidae.
Rubidgea is a genus of gorgonopsid from the upper Permian of South Africa and Tanzania, containing the species Rubidgea atrox. The generic name Rubidgea is sometimes believed to be derived from the surname of renowned Karoo paleontologist, Professor Bruce Rubidge, who has contributed to much of the research conducted on therapsids of the Karoo Basin. However, this generic name was actually erected in honor of Rubidge's paternal grandfather, Sydney Rubidge, who was a renowned fossil hunter. Its species name atrox is derived from Latin, meaning “fierce, savage, terrible”. Rubidgea is part of the gorgonopsian subfamily Rubidgeinae, a derived group of large-bodied gorgonopsians restricted to the Late Permian (Lopingian). The subfamily Rubidgeinae first appeared in the Tropidostoma Assemblage Zone. They reached their highest diversity in the Cistecephalus and Daptocephalus assemblage zones of the Beaufort Group in South Africa.
Lemurosaurus is a genus of extinct biarmosuchian therapsids from the Late Permian of South Africa. The generic epithet Lemursaurus is a mix of Latin, lemures “ghosts, spirits”, and Greek, sauros, “lizard”. Lemurosaurus is easily identifiable by its prominent eye crests, and large eyes. The name Lemurosaurus pricei was coined by paleontologist Robert Broom in 1949, based on a single small crushed skull, measured at approximately 86 millimeters in length, found on the Dorsfontein farm in Graaff-Reinet. To date, only two skulls of the Lemurosaurus have been discovered, so body size is unknown. The second larger, more intact, skull was found in 1974 by a team from the National Museum, Bloemfontein.
Burnetia is an extinct genus of biarmosuchian therapsids in the family Burnetiidae, from the Late Permian of South Africa. Burnetia is known so far from a single holotype skull lacking the lower jaws described by South African paleontologist Robert Broom in 1923. Due to erosion and dorsoventral crushing, features of the skull are hard to interpret. Stutural lines are further distorted by the unusual shape of the skull roof, including many bosses and protuberances.
Paraburnetia is an extinct genus of biarmosuchian therapsids from the Late Permian of South Africa. It is known for its species P. sneeubergensis and belongs to the family Burnetiidae. Paraburnetia lived just before the Permian–Triassic mass extinction event.
Eriphostoma is an extinct genus of gorgonopsian therapsids known from the Middle Permian of Tapinocephalus Assemblage Zone, South Africa. It has one known species, Eriphostoma microdon, and was first named by Robert Broom in 1911. It is the oldest known gorgonopsian and among the smallest and most basal members of the clade.
Lycaenodon is an extinct genus of biarmosuchian therapsids from the Late Permian of South Africa. It is known from a single species, Lycaenodon longiceps, which was named by South African paleontologist Robert Broom in 1925. Both are small-bodied biarmosuchians. Two specimens are known, and both preserve only the front portions of the skull. These specimens come from the Cistecephalus Assemblage Zone of the Karoo Basin. Broom attributed the back portion of a third skull to Lycaenodon, but subsequent examiners considered it to belong to a gorgonopsian or dinocephalian and not a biarmosuchian. Most of the distinguishing features of Lycaenodon come from its palate. As a member of Biarmosuchia, the most basal group of therapsids, Lycaenodon shares many features with earlier and less mammal-like synapsids like Dimetrodon.
Trochosuchus is a dubious genus of therocephalian therapsid from the middle Permian (Capitanian) of South Africa based on a weathered and poorly preserved undiagnostic fossil of a lycosuchid therocephalian. It includes the type and only species, T. acutus. Trochosuchus was named by palaeontologist Robert Broom in 1908 based on its supposedly unique proportions of the simulatenous 'double' functional canines thought to be characteristic of lycosuchids, with the pair in front being noticeably smaller than the second pair behind.
Herpetoskylax is an extinct genus of biarmosuchians which existed in South Africa. The type species is Herpetoskylax hopsoni. It lived in the Late Permian Period.
"Dixeya" nasuta is a species of the predatory gorgonopsian therapsids from the Late Permian of East Africa, known from fossils found in what is now Tanzania. The species has a complicated taxonomic history, it was originally named as a second species of the genus Dixeya which is now considered a junior synonym of Aelurognathus. "D." nasuta itself, however, was not moved to Aelurognathus, and although it was instead tentatively referred to Arctognathus at first it has since been recognised to not belong to this genus either. This situation leaves "Dixeya" nasuta without a formal genus name. It was proposed to belong to a new distinct genus, named "Njalila", that was informally proposed for the species in a PhD thesis, but this name has not yet been formally published and is currently a nomen nudum. "D." nasuta has been characterised from other gorgonopsians by a combination of its straight snout profile, upturned and "pinched" nose, and curved jaw margin.
Leucocephalus is a genus of biarmosuchian belonging to the family Burnetiidae dating to the Wuchiapingian. It was found in the Tropidostoma Assemblage Zone of the Main Karoo Basin of South Africa. It is a monotypic taxon which contains one only species, Leucocephalus wewersi. The genus name Leucocephalus is derived from Greek. Leucos, meaning white; kephalos, meaning skull, as the Leucocephalus skull discovered was unusually pale. The species epithet wewersi comes from the farm employee who found the skull, Klaus ‘Klaasie’ Wewers.
