Dinocephalians are a clade of large-bodied early therapsids that flourished in the Early and Middle Permian between 279.5 and 260 million years ago (Ma), but became extinct during the Capitanian mass extinction event. Dinocephalians included herbivorous, carnivorous, and omnivorous forms. Many species had thickened skulls with many knobs and bony projections. Dinocephalians were the first non-mammalian therapsids to be scientifically described and their fossils are known from Russia, China, Brazil, South Africa, Zimbabwe, and Tanzania.
Pareiasaurs are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with osteoderms 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.
Anthodon is an extinct genus of pareiasaurid parareptile from the Permian period of South Africa and Tanzania.
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.
Anteosaurs are a group of large, primitive carnivorous dinocephalian therapsids with large canines and incisors and short limbs, that are known from the Middle Permian of South Africa, Russia, China, and Brazil. Some grew very large, with skulls 50–80 centimetres (20–31 in) long, and were the largest predators of their time. They died out at the end of the Middle Permian, possibly as a result of the extinction of the herbivorous Tapinocephalia on which they may have fed.
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.
Estemmenosuchidae is an extinct family of large, very early herbivorous therapsids that flourished during the Guadalupian period. They are distinguished by horn-like structures, probably for display or agonistic behavior. Apart from the best known genus, Estemmenosuchus, the group is poorly known. To date, their fossils are known only from the Perm region of Russia.
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".
Cotylorhynchus is an extinct genus of herbivorous caseid synapsids that lived during the late Lower Permian (Kungurian) and possibly the early Middle Permian (Roadian) in what is now Texas and Oklahoma in the United States. The large number of specimens found make it the best-known caseid. Like all large herbivorous caseids, Cotylorhynchus had a short snout sloping forward and very large external nares. The head was very small compared to the size of the body. The latter was massive, barrel-shaped, and ended with a long tail. The limbs were short and robust. The hands and feet had short, broad fingers with powerful claws. The barrel-shaped body must have housed large intestines, suggesting that the animal had to feed on a large quantity of plants of low nutritional value. Caseids are generally considered to be terrestrial, though a semi-aquatic lifestyle has been proposed by some authors. The genus Cotylorhynchus is represented by three species, the largest of which could reach more than 6 m in length. However, a study published in 2022 suggests that the genus may be paraphyletic, with two of the three species possibly belonging to separate genera.
Batrachotomus is a genus of prehistoric archosaur. Fossils of this animal have been found in southern Germany and dated from the Ladinian stage of the Middle Triassic period, around 242 to 237 million years ago. Batrachotomus was described by palaeontologist David J. Gower 22 years after its discovery.
Ennatosaurus is an extinct genus of caseid synapsid that lived during the Middle Permian in northern European Russia. The genus is only represented by its type species, Ennatosaurus tecton, which was named in 1956 by Ivan Antonovich Efremov. The species is known from at least six skulls associated with their lower jaws, as well as from the postcranial bones of several juvenile individuals. Ennatosaurus has the typical caseid skull with a short snout tilted forward and very large external nares. However, it differs from other derived caseids by its postcranial skeleton with smaller proportions compared to the size of the skull. As with other advanced caseids, the teeth of Ennatosaurus were well suited for slicing and cutting vegetation. The presence of a highly developed hyoid apparatus indicates the presence of a massive and mobile tongue, which had to work in collaboration with the palatal teeth during swallowing. With a late Roadian - early Wordian age, Ennatosaurus is one of the last known caseids.
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.
Rhipaeosaurus is an extinct genus of nycteroleterid parareptile known from an articulated skeleton from the mid Middle Permian of European Russia. It contained a single species, Rhipaeosaurus tricuspidens. A bayesian analysis suggests that it is more closely related to pareiasaurs than to the other nycteroleterids, due to skull and tooth features. For this reason, "Nycteroleteridae" may be a grade rather than a clade, unless redefined to exclude Rhipaeosaurus.
Aerosaurus is an extinct genus within Varanopidae, a family of non-mammalian synapsids. It lived between 252-299 million years ago during the Early Permian in North America. The name comes from Latin aes (aeris) “copper” and Greek sauros “lizard,” for El Cobre Canyon in northern New Mexico, where the type fossil was found and the site of former copper mines. Aerosaurus was a small to medium-bodied carnivorous synapsid characterized by its recurved teeth, triangular lateral temporal fenestra, and extended teeth row. Two species are recognized: A. greenleeorum (1937) and A. wellesi (1981).
Deltavjatia was a pareiasauromorph procolophonoid from the Tatarian stage of the Permian time period. It had a large body of about 1.5 m (4.9 ft) in length. Deltavjatia was an herbivore and lived in what is now Russia. The first specimen of Deltavjatia was a specimen of a skull and lower mandible, found in the Urpalov Formation in Kotelnich, Vyatka River. Since then, numerous mostly complete skeletons have been found, many of them being so well preserved due to the silty, anaerobic environment of the Kotelnich deposits that fossilised white blood cells are able to be distinguished in them. Analyses of the bone histology of Deltavjatia show that they grew very rapidly during the early stages of their ontogeny but that their growth rate drastically slowed down once they reached approximately half of their full body size.
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.
Pareiasauromorpha is a group of parareptilian amniotes from the Permian. It includes genera found all over the world, with many genera from Asia and South Africa. The clade was first used as a group by Linda A. Tsuji in 2011, in order to group the family Nycteroleteridae (nycteroleters) and the superfamily Pareiasauroidea (pareiasaurs). Pareiasauromorpha is considered to be a monophyletic node, the sister group to procolophonoids.
