Synapsids are one of the two major clades of vertebrate animals in the group Amniota, the other being the sauropsids, which include reptiles and birds. The synapsids were the dominant land animals in the late Paleozoic and early Mesozoic, but the only extant group that survived into the Cenozoic are the mammals. Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye orbit, leaving a bony arch beneath each; this accounts for their name. The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals.
Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. The mouths of lungfish typically bear tooth plates, which are used to crush hard shelled organisms.
"Labyrinthodontia" is an informal grouping of extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras. Traditionally considered a subclass of the class Amphibia, modern classification systems recognize that labyrinthodonts are not a formal natural group (clade) exclusive of other tetrapods. Instead, they consistute an evolutionary grade, ancestral to living tetrapods such as lissamphibians and amniotes. "Labyrinthodont"-grade vertebrates evolved from lobe-finned fishes in the Devonian, though a formal boundary between fish and amphibian is difficult to define at this point in time.
Caseidae are an extinct family of basal synapsids that lived from the Late Carboniferous to Middle Permian between about 300 and 265 million years ago. Fossils of these animals come from the south-central part of the United States, from various parts of Europe, and possibly from South Africa if the genus Eunotosaurus is indeed a caseid as some authors proposed in 2021. Caseids show great taxonomic and morphological diversity. The most basal taxa were small insectivorous and omnivorous forms that lived mainly in the Upper Carboniferous and Lower Permian, such as Eocasea, Callibrachion, and Martensius. This type of caseid persists until the middle Permian with Phreatophasma and may be Eunotosaurus. During the early Permian, the clade is mainly represented by many species that adopted a herbivorous diet. Some have evolved into gigantic forms that can reach 6–7 metres (20–23 ft) in length, such as Cotylorhynchus hancocki and Alierasaurus ronchii, making them the largest Permian synapsids. Caseids are considered important components of early terrestrial ecosystems in vertebrate history because the numerous herbivorous species in this family are among the first terrestrial tetrapods to occupy the role of primary consumer. The caseids experienced a significant evolutionary radiation at the end of the early Permian, becoming, with the captorhinid eureptiles, the dominant herbivores of terrestrial ecosystems in place of the edaphosaurids and diadectids.
Microsauria is an extinct, possibly polyphyletic order of amphibians from the late Carboniferous and early Permian periods. It is the most diverse and species-rich group of lepospondyls. Recently, Microsauria has been considered paraphyletic, as several other non-microsaur lepospondyl groups such as Lysorophia seem to be nested in it. Microsauria is now commonly used as a collective term for the grade of lepospondyls that were originally classified as members of Microsauria.
The Tapinocephalus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 2,000 metres (6,600 ft), occur from Merweville and Leeu-Gamka in its southernmost exposures, from Sutherland through to Beaufort West where outcrops start to only be found in the south-east, north of Oudshoorn and Willowmore, reaching up to areas south of Graaff-Reinet. Its northernmost exposures occur around the towns Fraserburg and Victoria West. The Tapinocephalus Assemblage Zone is the second biozone of the Beaufort Group.
The Daptocephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the upper Teekloof Formation west of 24°E, the majority of the Balfour Formation east of 24°E, and the Normandien Formation in the north. It has numerous localities which are spread out from Colesberg in the Northern Cape, Graaff-Reniet to Mthatha in the Eastern Cape, and from Bloemfontein to Harrismith in the Free State. The Daptocephalus Assemblage Zone is one of eight biozones found in the Beaufort Group and is considered Late Permian (Lopingian) in age. Its contact with the overlying Lystrosaurus Assemblage Zone marks the Permian-Triassic boundary.
The Pristerognathus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Abrahamskraal Formation and lowermost Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching not more than 300 metres (980 ft), occur just east of Sutherland through to Beaufort West in the south and Victoria West in the north. Exposures are also found west of Colesberg and south of Graaff-Reinet. The Pristerognathus Assemblage Zone is the third biozone of the Beaufort Group.
The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.
Limnoscelis was a genus of large diadectomorph tetrapods from the Late Carboniferous of western North America. It includes two species: the type species Limnoscelis paludis from New Mexico, and Limnoscelis dynatis from Colorado, both of which are thought to have lived concurrently. No specimens of Limnoscelis are known from outside of North America. Limnoscelis was carnivorous, and likely semiaquatic, though it may have spent a significant portion of its life on land. Limnoscelis had a combination of derived amphibian and primitive reptilian features, and its placement relative to Amniota has significant implications regarding the origins of the first amniotes.
Lobalopex is an extinct genus of biarmosuchian therapsids. It was alive during the Late Permian and has only been found in the Teekloof Formation in South Africa. The only known species of the genus is Lobalopex mordax. Lobalopex is part of the clade of Burnetiamorpha, which have fossil specimens located in multiple areas of Africa and Russia.
Gnathorhiza is an extinct genus of prehistoric lobe-finned fish (lungfish) which lived from the Carboniferous period to the Early Triassic epoch. It is the only known lungfish genus to have crossed the Permo-Triassic boundary. Several species have been described, ranging in size from 5 to 50 centimeters.
Microposaurus is an extinct genus of trematosaurid temnospondyl. Fossils are known from the Cynognathus Assemblage Zone of the Beaufort Group in South Africa and the Rouse Hill Siltstone of Australia that date back to the Anisian stage of the Middle Triassic. These aquatic creatures were the short snouted lineage from Trematosaurinae.
Dicynodontoides is a genus of small to medium-bodied, herbivorous, emydopoid dicynodonts from the Late Permian. The name Dicynodontoides references its “dicynodont-like” appearance due to the caniniform tusks featured by most members of this infraorder. Kingoria, a junior synonym, has been used more widely in the literature than the more obscure Dicynodontoides, which is similar-sounding to another distantly related genus of dicynodont, Dicynodon. Two species are recognized: D. recurvidens from South Africa, and D. nowacki from Tanzania.
Pelanomodon is an extinct genus of dicynodont therapsids that lived in the Late Permian period. Fossil evidence of this genus is principally found in the Karoo Basin of South Africa, in the Dicynodon Assemblage Zone. Lack of fossil record after the Late Permian epoch suggests that Pelanomodon fell victim to the Permian-Triassic extinction event.
Kombuisia is a genus of dicynodont from Early to Middle Triassic of South Africa and Antarctica. Two species were described for the genus: Kombuisia frerensis (type) and Kombuisia antarctica.
Syops is an extinct genus of dicynodont therapsid. The type species S. vanhoepeni was first named in 1938 as Dicynodon vanhoepeni. Fossils of the genus have been found in the Cistecephalus Assemblage Zone in the Usili Formation of the Ruhuhu Basin, Tanzania and the Upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia. Its phylogenetic placement is somewhat uncertain, with multiple different studies finding it as either a basal geikiid, rhachiocephalid a dicynodontoid more derived than the most basal genera but less derived than Lystrosauridae, or a lystrosaurid.
The Red Beds of Texas and Oklahoma are a group of Early Permian-age geologic strata in the southwestern United States cropping out in north-central Texas and south-central Oklahoma. They comprise several stratigraphic groups, including the Clear Fork Group, the Wichita Group, and the Pease River Group. The Red Beds were first explored by American paleontologist Edward Drinker Cope starting in 1877. Fossil remains of many Permian tetrapods have been found in the Red Beds, including those of Dimetrodon, Edaphosaurus, Seymouria, Platyhystrix, and Eryops. A recurring feature in many of these animals is the sail structure on their backs.
Huskerpeton is an extinct genus of recumbirostran from the Early Permian period. They belong to the order Microsauria, which was established in 1863 by Dawson, and was quickly expanded to include many different small taxa. They lived in what is now Nebraska and Kansas. The holotype of Huskerpeton was uncovered at the Eskridge formation in Nebraska, which is part of how it got its name.
Ceratodontiformes is the only extant order of lungfish, containing the families Neoceratodontidae, Lepidosirenidae, and Protopteridae as well as many other extinct groups. Members of this group are the only lungfish known to have survived the Permian-Triassic extinction event. Although lungfish originated in marine environments, the Ceratodontiformes have been an exclusively freshwater group since the Carboniferous.
