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.
Inostrancevia is an extinct genus of carnivorous therapsids, containing the largest members of gorgonopsians, predators characterized by long, saber-tooth-like canines. The various species inhabited European Russia during the Upper Tatarian (Vyatskian), a Russian regional stage equivalent to the Wuchiapingian and Changhsingian stage of the Late Permian period, dating from approximately 259 to 252.3 million years ago. The genus name was described posthumously, after the Bolshevik Revolution, by the Russian paleontologist Vladimir P. Amalitsky in 1922, in honor of geologist Aleksandr Inostrantsev.
Therocephalia is an extinct suborder of eutheriodont therapsids from the Permian and Triassic. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their teeth, suggest that they were carnivores. Like other non-mammalian synapsids, therocephalians were once described as "mammal-like reptiles". Therocephalia is the group most closely related to the cynodonts, which gave rise to the mammals. This relationship takes evidence in a variety of skeletal features.
Euchambersia is an extinct genus of therocephalian therapsids that lived during the Late Permian, approximately between 256 and 255 million years ago, 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.
Moschorhinus is an extinct genus of therocephalian in the family Akidnognathidae with only one species: M. kitchingi. It was a carnivorous synapsid which has been found in the Late Permian to Early Triassic of the South African Karoo Supergroup. It was a large carnivore, reaching 1.5 m (4.9 ft) in total body length with the largest skull comparable to that of a lion in size. It had a broad, blunt snout which bore long, straight canines. It appears to have replaced the gorgonopsids ecologically, and hunted much like a big cat. While most abundant in the Late Permian, it survived a little after the Permian Extinction, though these Triassic individuals had stunted growth.
Lycosuchus is an extinct genus of carnivorous therocephalians which lived in the Middle Permian 265—260 Ma existing for approximately 5 million years. As a member of the Lycosuchidae, the genus represents one of the earliest diverging therocephalians. The type species Lycosuchus vanderrieti is known from a handful of well-preserved specimens featuring the cranium and lower jaw; the holotype US D173 housed at the University of Stellenbosch, South Africa, is a near complete occluded skull. Specimen MB.R. 995, housed at the Museum für Naturkunde Berlin, Germany, consists of a near complete and isolated lower jaw, along with a partial snout and brain case. With the help of μCT data, Pusch et al (2020) described the endocranial anatomy of Lycosuchus vanderrieti.
Theriognathus is an extinct genus of therocephalian therapsid belonging to the family Whaitsiidae, known from fossils from South Africa, Zambia, and Tanzania. Theriognathus has been dated as existing during the Late Permian. Although Theriognathus means mammal jaw, the lower jaw is actually made up of several bones as seen in modern reptiles, in contrast to mammals. Theriognathus displayed many different reptilian and mammalian characteristics. For example, Theriognathus had canine teeth like mammals, and a secondary palate, multiple bones in the mandible, and a typical reptilian jaw joint, all characteristics of reptiles. It is speculated that Theriognathus was either carnivorous or omnivorous based on its teeth, and was suited to hunting small prey in undergrowth. This synapsid adopted a sleek profile of a mammalian predator, with a narrow snout and around 1 meter long. Theriognathus is represented by 56 specimens in the fossil record.
Regisaurus is an extinct genus of small carnivorous therocephalian. It is known from a single described species, the type species Regisaurus jacobi, from the Early Triassic Lystrosaurus Assemblage Zone of South Africa, although at least one undescribed species is also known.
Microgomphodon is an extinct genus of therocephalian therapsid from the Middle Triassic of South Africa and Namibia. Currently only one species of Microgomphodon, M. oligocynus, is recognized. With fossils present in the Cynognathus Assemblage Zone (CAZ) of the Burgersdorp Formation in South Africa and Omingonde Formation of Namibia and ranging in age from late Olenekian to Anisian, it is one of the most geographically and temporally widespread therocephalian species. Moreover, its occurrence in the upper Omigonde Formation of Namibia makes Microgomphodon the latest-surviving therocephalian. Microgomphodon is a member of the family Bauriidae and a close relative of Bauria, another South African bauriid from the CAZ. Like other bauriids, it possesses several mammal-like features such as a secondary palate and broad, molar-like postcanine teeth, all of which evolved independently from mammals.
Vjushkovisaurus is an extinct genus of Middle Triassic archosauriform. It is known from the Anisian-aged Donguz Gorizont in Sol-Iletsk, Orenburg Oblast, Russia. The genus was named in 1982, with the type species being V. berdjanensis. Material has been collected in the Berdyanka II locality from a fossil assemblage called the Eryosuchus Fauna along the Berdyanka River, specifically in a sand-carbonate concretion in the upper part of the main river channel. Vjushkovisaurus is known only from the holotype PIN 2865/62, a partial postcranial skeleton which consists of 12 presacral vertebrae, left humerus, ribs, a fragment of the coracoid and a fragment of the fibula.
Bauriidae is an extinct family of therocephalian therapsids. Bauriids were the latest-surviving group of therocephalians after the Permian–Triassic extinction event, going extinct in the Middle Triassic. They are among the most advanced eutherocephalians and possess several mammal-like features such as a secondary palate and wide postcanine teeth at the back of the jaws. Unlike other therocephalians, bauriids were herbivorous. They were also smaller than earlier members of the group. Two subfamilies are classified within Bauriidae: Nothogomphodontinae and Bauriinae.
Purlovia is an extinct genus of herbivorous therocephalian therapsids from the Late Permian of Russia. Together with the closely related South African genus Nanictidops, it is a member of the family Nanictidopidae. Fossils have been found from the Tonshayevsky District of Nizhny Novgorod Oblast. The type species of Purlovia, P. maxima, was named in 2011.
Choerosaurus is an extinct genus of therocephalian therapsids from the Late Permian of South Africa. The type species Choerosaurus dejageri was named by South African paleontologist Sidney H. Haughton from the Tropidostoma Assemblage Zone in 1929.
Blattoidealestes is an extinct genus of therocephalian therapsid from the Middle Permian of South Africa. The type species Blattoidealestes gracilis was named by South African paleontologist Lieuwe Dirk Boonstra from the Tapinocephalus Assemblage Zone in 1954. Dating back to the Middle Permian, Blattoidealestes is one of the oldest therocephalians. It is similar in appearance to the small therocephalian Perplexisaurus from Russia, and may be closely related.
Macroscelesaurus is an extinct genus of therocephalian therapsid from the Late Permian of South Africa. The type species Macroscelesaurus janseni was named by Sidney H. Haughton in 1918 from the Cistecephalus Assemblage Zone. It is one of the few therocephalians known from postcranial remains.
Karenites is an extinct genus of therocephalian therapsids from the Late Permian of Russia. The only species is Karenites ornamentatus, named in 1995. Several fossil specimens are known from the town of Kotelnich in Kirov Oblast.
Phthinosuchia is an extinct group of therapsids including two poorly known species, Phthinosuchus discors and Phthinosaurus borrisiaki, from the Middle Permian of Russia. Phthinthosuchus is known a partial crushed skull and Phthinosaurus is known from an isolated lower jaw. The two species have traditionally been grouped together based on their shared primitive characteristics, but more recent studies have proposed that they are more distantly related. Phthinosuchus is either a carnivorous gorgonopsian relative or an anteosaurian dinocephalian while Phthinosaurus is either a herbivorous rhopalodont dinocephalian or a therocephalian.
Phthinosaurus is an extinct genus of therapsids from the Middle Permian of Russia. The type species Phthinosaurus borrisiaki was named by Soviet paleontologist Ivan Yefremov in 1940 on the basis of an isolated lower jaw. Because this jaw provides few distinguishing characteristics, the evolutionary relationships of Phthinosaurus are poorly known. Yefremov named the family Phthinosuchidae in 1954 to include Phthinosaurus and the newly named Phthinosuchus, which was described on the basis of a crushed partial skull. American paleontologist Everett C. Olson placed both of these therapsids in the larger infraorder Phthinosuchia in 1961. In 1974 Leonid Tatarinov named the family Phthinosauridae to include Phthinosaurus alone, retaining Phthinosuchus within Phthinosuchidae.
Gorynychus is a genus of therocephalian from the mid-Permian from Kotelnich, Russia. The genus contains two species, G. masyutinae and G. sundyrensis. It was named after the three-headed dragon Zmey Gorynych from Russian mythology.
Nochnitsa is a genus of gorgonopsian therapsid from the Kotelnich red beds of Permian Russia. It contains one species, Nochnitsa geminidens. It the most basal known gorgonopsian and among the smallest members of the clade known to date.
