An anapsid is an amniote whose skull lacks one or more skull openings (fenestra) near the temples. Traditionally, the Anapsida are the most primitive subclass of amniotes, the ancestral stock from which Synapsida and Diapsida evolved, making anapsids paraphyletic. It is however doubtful that all anapsids lack temporal fenestra as a primitive trait, and that all the groups traditionally seen as anapsids truly lacked fenestra.
Pareiasaurs are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permian, before becoming globally distributed during the Late Permian. Pareiasaurs were the largest reptiles of the Permian, reaching sizes equivalent to those of contemporary therapsids. Pareiasaurs became extinct at the end of the Permian during the Permian-Triassic extinction event.
Biarmosuchus is an extinct genus of biarmosuchian therapsids that lived around 267 mya during the Middle Permian period. Biarmosuchus was discovered in the Perm region of Russia. The first specimen was found in channel sandstone that was deposited by flood waters originating from the young Ural Mountains.
Scutosaurus is an extinct genus of pareiasaur parareptiles. Its genus name refers to large plates of armor scattered across its body. It was a large anapsid reptile that, unlike most reptiles, held its legs underneath its body to support its great weight. Fossils have been found in the Sokolki Assemblage Zone of the Malokinelskaya Formation in European Russia, close to the Ural Mountains, dating to the late Permian (Lopingian) between 264 and 252 million years ago.
Parareptilia is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia. Parareptiles first arose near the end of the Carboniferous period and achieved their highest diversity during the Permian period. Several ecological innovations were first accomplished by parareptiles among reptiles. These include the first reptiles to return to marine ecosystems (mesosaurs), the first bipedal reptiles, the first reptiles with advanced hearing systems, and the first large herbivorous reptiles. The only parareptiles to survive into the Triassic period were the procolophonoids, a group of small generalists, omnivores, and herbivores. The largest family of procolophonoids, the procolophonids, rediversified in the Triassic and continued to be successful until their demise in the Triassic-Jurassic mass extinction.
Elginia is an extinct genus of pareiasaurid known from the Late Permian of Scotland and China. It was named for the area around Elgin in Scotland, which has yielded many fossils referred to as the Elgin Reptiles.
The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria but are now considered a clade of Parareptilia. They are closely related to other generally lizard-like Permian reptiles such as the Millerettidae, Bolosauridae, Acleistorhinidae, and Lanthanosuchidae, all of which are included under the Anapsida or "Parareptiles".
Procolophonomorpha is an order or clade containing most parareptiles. Many papers have applied various definitions to the name, though most of these definitions have since been considered synonymous with modern parareptile clades such as Ankyramorpha and Procolophonia. The current definition of Procolophonomorpha, as defined by Modesto, Scott, & Reisz (2009), is that of as a stem-based group containing Procolophon and all taxa more closely related to it than to Milleretta. It constitutes a diverse assemblage that includes a number of lizard-like forms, as well as more diverse types such as the pareiasaurs. Lee 1995, 1996, 1997 argues that turtles evolved from pareiasaurs, but this view is no longer considered likely. Rieppel and deBraga 1996 and deBraga and Rieppel, 1997 argue that turtles evolved from sauropterygians, and there is both molecular and fossil (Pappochelys) evidence for the origin of turtles among diapsid reptiles.
Nyctiphruretus is an extinct genus of nyctiphruretid parareptile known from the Guadalupian series of European Russia.
Procolophon is a genus of lizard-like procolophonid reptiles that first appeared in the Late Permian (Lopingian) of South Africa, Brazil, and Antarctica. It persisted through the Permian–Triassic extinction event, but went extinct in the early Triassic. The type species is P. trigoniceps.
Macroleter is an extinct genus of nycteroleterid parareptile which existed in Oklahoma and Russia during the upper Permian period. It was a quite generalized primitive reptile, in many ways resembling their amphibian ancestors. It was first named by paleontologists Tverdochlebova and Ivachnenko in 1984. According to classification by Michel Laurin and Robert R. Reisz, the genus is a parareptile, belonging to the same branch as Millerettidae, Procolophonidae and other generalized anapsid reptiles. The type species is Macroleter poezicus from Upper Permian of Russia.
Nycteroleter is an extinct genus of nycteroleterid parareptile known from the Middle Permian of European Russia. Fossils were first found in the Mezen River, near to Arkhangelsk. Within the Nycteroleteridae, it is considered most closely related to Emeroleter. However, its legs were shorter than those of Emeroleter and its skull was flatter. Nycteroleter was insectivorous, and may have been nocturnal. It was a small animal, less than a metre long.
Emeroleter is an extinct genus of nycteroleterid parareptile known from the early Late Permian of European Russia. It was a long-legged lizard-like small animal with a length about 30 cm.
Progalesaurus is an extinct genus of galesaurid cynodont from the early Triassic. Progalesaurus is known from a single fossil of the species Progalesaurus lootsbergensis, found in the Lystrosaurus Assemblage Zone of the Balfour Formation. Close relatives of Progalesaurus, other galesaurids, include Galesaurus and Cynosaurus. Galesaurids appeared just before the Permian-Triassic extinction event, and disappeared from the fossil record in the Middle-Triassic.
Phreatophasma is an extinct genus of synapsids from the Middle Permian of European Russia. It includes only one species, Phreatophasma aenigmatum, which is itself known from a single femur found in a mine near the town of Belebei in Bashkortostan. Phreatophasma comes from a fossil assemblage that is latest Ufimian to earliest Kazanian in age under the Russian stratigraphic scheme, correlating with the Roadian Age under the international stratigraphic timescale. Because the species is based on a single specimen with few diagnostic anatomical features, uncertainty remains as to where it belongs in tetrapod phylogeny; originally interpreted in 1954 as an enigmatic "theromorph" synapsid by Soviet paleontologist Ivan Yefremov, Phreatophasma was later described as a therapsid incertae sedis by American paleontologist Alfred Romer in 1956 and then as a member of a basal synapsid family called Caseidae starting with Everett C. Olson in 1962. Olson's classification was later supported by Canadian paleontologist Robert Reisz in 1986 and American paleontologist Robert L. Carroll in 1988. Ivakhneneko et al. (1997) and Maddin et al. (2008) both considered Phreatophasma an indeterminate synapsid.
Owenetta is an extinct genus of owenettid procolophonian parareptile. Fossils have been found from the Beaufort Group in the Karoo Basin of South Africa. Although most procolophonians lived during the Triassic, Owenetta existed during the Wuchiapingian and Changhsingian stages of the Late Permian as well as the early Induan stage of the Early Triassic. It is the type genus of the family Owenettidae, and can be distinguished from other related taxa in that the posterior portion of the supratemporal bears a lateral notch and that the pineal foramen is surrounded by a depressed parietal surface on the skull table.
Microleter is an extinct genus of basal procolophonomorph parareptiles which lived in Oklahoma during the Early Permian period. The type and only known species is Microleter mckinzieorum. Microleter is one of several parareptile taxa described from the Richards Spur fissure fills, and can be characterized from its high tooth count, lacrimal/narial contact, short postfrontal, and slit-like temporal emargination edged by the postorbital, jugal, squamosal, and quadratojugal. Contrary to Australothyris, which had a similar phylogenetic position as a basal procolophonomorph, Microleter suggests that early parareptile evolution occurred in Laurasia and that multiple lineages developed openings or emarginations in the temporal region.
Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States.
Bunostegos is an extinct genus of pareiasaur parareptile from the Late Permian of the Agadez Region in Niger. The type species, Bunostegos akokanensis, was named from the Moradi Formation in 2003. It was a cow-sized animal with a distinctive skull that had large bony knobs, similar in form to those of other pareiasaurs but far larger. The species appears to have lived in a desert in the centre of the supercontinent of Pangaea.
Nycteroleteridae is a family of procolophonian parareptilians from the Middle to Late Permian of Russia and North America. They are sometimes classified as a sister group to pareiasaurids. The group includes the genera Macroleter, Bashkyroleter, "Bashkyroleter" mesensis, Nycteroleter, Emeroleter, and probably Rhipaeosaurus. They were carnivorous, and occasionally ate insects. The group was most common in European Russia, with only a few fossils in North America. One fossil has also been found in Africa, but this is the only one from Gondwana.
