Microsauria is an extinct, possibly polyphyletic order of tetrapods 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.
Asaphestera is an extinct genus of a synapsid described on the basis of fossils from the Carboniferous of the Joggins locality in Nova Scotia, Canada. It was originally described as an undetermined lepospondyl and subsequently classified as a microsaur within the family Tuditanidae. A study published in May 2020 found that specimens referred to Asaphestera represented several unrelated species. Steen (1934)'s original species name Asaphestera platyris was retained for a skull which has been re-evaluated as the earliest known synapsid.
Batropetes is an extinct genus of brachystelechid recumbirostran "microsaur". Batropetes lived during the Sakmarian stage[a] of the Early Permian. Fossils attributable to the type species B. fritschi have been collected from the town of Freital in Saxony, Germany, near the city of Dresden. Additional material has been found from the Saar-Nahe Basin in southwestern Germany and has been assigned to three additional species: B. niederkirchensis, B. palatinus, and B. appelensis.
Carrolla is an extinct genus of brachystelechid 'microsaur' that lived in the Lower Permian in North America. It was named in 1986 by American paleontologists Wann Langston and Everett Olson. The type species, Carrolla craddocki, is the only known species.
Hapsidopareion is an extinct genus of microsaur belonging to the family Hapsidopareiidae. Fossils have been found in the early Permian of Oklahoma.
Llistrofus is an extinct genus of early Permian microsaur within the family Hapsidopareiidae that is known from Oklahoma.
Odonterpeton is an extinct genus of "microsaur" from the Late Carboniferous of Ohio, containing the lone species Odonterpeton triangulare. It is known from a single partial skeleton preserving the skull, forelimbs, and the front part of the torso. The specimen was found in the abandoned Diamond Coal Mine of Linton, Ohio, a fossiliferous coal deposit dated to the late Moscovian stage, about 310 million years ago.
Rhynchonkos is an extinct genus of rhynchonkid microsaur. Originally known as Goniorhynchus, it was renamed in 1981 because the name had already been given to another genus; the family, likewise, was originally named Goniorhynchidae but renamed in 1988. The type and only known species is R. stovalli, found from the Early Permian Fairmont Shale in Cleveland County, Oklahoma. Rhynchonkos shares many similarities with Eocaecilia, an early caecilian from the Early Jurassic of Arizona. Similarities between Rhynchonkos and Eocaecilia have been taken as evidence that caecilians are descendants of microsaurs. However, such a relationship is no longer widely accepted.
Quasicaecilia is an extinct genus of microsaur. It is known from the Early Permian of Texas in the United States. A single specimen is known, collected from the Texas Permian redbeds by Charles Hazelius Sternberg in 1917. It was originally identified as a specimen of the gymnarthrid microsaur Cardiocephalus. The skull is small, less than 2 centimetres (0.79 in) in length, and the otic capsule is very large in comparison to the rest of the skull. The skull of Quasicaecilia superficially resembles those of extant but unrelated caecilians, hence the genus name. Quasicaecilia was assigned to the new family Brachystelechidae in 1991 along with the genera Batropetes and Carrolla.
Pariotichus is an extinct genus of gymnarthrid microsaurs from the early Permian of Texas.
Hyloplesion is an extinct genus of microbrachomorph microsaur. It is the type and only genus within the family Hyloplesiontidae. Fossils have been found from the Czech Republic near the towns of Plzeň, Nýřany, and Třemošná, and date back to the Middle Pennsylvanian. The type species is H. longicostatum, named in 1883. Two species belonging to different genera, Seeleya pusilla and Orthocosta microscopica, have been synonymized with H. longicostatum and are thought to represent very immature individuals.
Tuditanomorpha is a suborder of microsaur tetrapods. Tuditanomorphs lived from the Late Carboniferous to the Early Permian and are known from North America and Europe. Tuditanomorphs have a similar pattern of bones in the skull roof. Tuditanomorphs display considerable variability, especially in body size, proportions, dentition, and presacral vertebral count. Currently there are four families of tuditanomorphs, with two being monotypic. Tuditanids first appear in the Lower Pennsylvanian. Goniorhynchidae, Hapsidopareiidae, and Trihecatontidae appear in the Late Pennsylvanian and Early Permian.
Gymnarthridae is an extinct family of the group Recumbirostra. Gymnarthrids are known from Europe and North America and existed from the Late Carboniferous through the Early Permian. Remains have been found from the Czech Republic, Nova Scotia, Illinois, Texas, and Oklahoma. Previously they were considered tuditanomorph microsaurs.
Ostodolepidae, also spelled Ostodolepididae, is an extinct family of Early Permian tetrapods. Initially they were considered microsaurs, but later were assigned to the group Recumbirostra. Ostodolepids were relatively large, reaching lengths of up to 2 feet (61 cm), terrestrial, and presumably fossorial. Ostodolepid remains have been found from Early Permian beds in Texas, Oklahoma, and Germany.
Recumbirostra is a clade of tetrapods which lived during the Carboniferous and Permian periods. They are thought to have had a fossorial (burrowing) lifestyle and the group includes both short-bodied and long-bodied snake-like forms. At least one species, the long-bodied molgophid Nagini mazonense, lost its forelimbs entirely. Recumbirostra includes the families Pantylidae, Gymnarthridae, Ostodolepidae, Rhynchonkidae and Brachystelechidae, with additional families such as Microbrachidae and Molgophidae being included by some authors. Brachystelechidae and Molgophidae have also been grouped together in the suggested clade Chthonosauria.
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.
The Vale Formation is a geological formation in north-central Texas, a component of the Texas red beds preserving sediments and fossils from the Early Permian Leonardian series. It occupies the middle part of the Clear Fork Group, above the Arroyo Formation and below the Choza Formation. Some sources consider the Vale Formation to be merely an informal subunit of the Clear Fork Formation, thus renaming it to the Middle Clear Fork Formation.
Diabloroter is a Carboniferous genus of brachystelechid 'microsaur' from the Mazon Creek lagerstätte in Illinois. It was named in 2019 by Arjan Mann and Hillary C. Maddin.
Hillary Catherine Maddin is a Canadian paleontologist and developmental biologist known for her work on development in extinct and extant amphibians. She is currently an associate professor in the Department of Earth Sciences at Carleton University.
Joermungandr is an extinct genus of recumbirostran tetrapod from the Late Carboniferous Mazon Creek fossil beds of Illinois. It currently contains a single species, Joermungandr bolti. Like many other recumbirostrans, the body is elongated, which is likely an adaptation for fossoriality.
