Caecilians are a group of limbless, vermiform (worm-shaped) or serpentine (snake-shaped) amphibians with small or sometimes nonexistent eyes. They mostly live hidden in soil or in streambeds, and this cryptic lifestyle renders caecilians among the least familiar amphibians. Modern caecilians live in the tropics of South and Central America, Africa, and southern Asia. Caecilians feed on small subterranean creatures such as earthworms. The body is cylindrical and often darkly coloured, and the skull is bullet-shaped and strongly built. Caecilian heads have several unique adaptations, including fused cranial and jaw bones, a two-part system of jaw muscles, and a chemosensory tentacle in front of the eye. The skin is slimy and bears ringlike markings or grooves and may contain scales.
Dunkleosteus is an extinct genus of large arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first apex predators of any ecosystem.
Thrinaxodon is an extinct genus of cynodonts, including the species T. liorhinus which lived in what are now South Africa and Antarctica during the Early Triassic. Thrinaxodon lived just after the Permian–Triassic mass extinction event, its survival during the extinction may have been due to its burrowing habits.
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.
Dinilysia is an extinct genus of snake from the Late Cretaceous (Coniacian) of South America. Dinilysia was a relatively large ambush predator, measuring approximately 2 m (6.6 ft) long. The skull morphology of Dinilysia is similar to boids, suggesting that it was able to consume large prey. Living in a desert-like environment, Dinilysia is likely a terrestrial or a semi-fossorial animal.
Myosaurus is a genus of Anomodontia in the order Therapsida. They are also classified as Dicynodontia, which is a subclade of Anomodontia. The Mysosaurus was a small, herbivorous synapsid that existed around the early Triassic period. All of the fossils found of this species were found in Antarctica and South Africa. Compared to other fossils found from species that existed during this time, the Myosaurus is not common in the fossil record. This is due to a shortage of discovered fossils that possess characteristics unique to the Myosaurus. Notably, under 130 fossil fragments have been found that have been classified as Myosauridae, and almost all have been skulls. These skulls can be classified as Myosaurus because this species, unlike other dicynodonts, do not possess tusks or postfrontal teeth. The only species identified in the family Myosauridae is the Myosaurus gracilis, or M. gracilis. It should be recognized that the Myosaurus is almost always referred to as the M. gracilis in scientific research.
Batropetes is an extinct genus of brachystelechid recumbirostran "microsaur". Batropetes lived during the Sakmarian stage 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.
Euryodus is an extinct genus of microsaur within the family Gymnarthridae. Euryodus is a Lepospondyl from the clade Microsauria that lived during the Lower Permian. The name comes from Greek, meaning ‘broad-tooth’. It has been found in the southern half of North America, from its original discovery in Texas up to Utah.
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.
Stegotretus is an extinct genus of microsaur referred to the Pantylidae. It is known from the Carboniferous–Permian boundary Cutler Formation exposures of New Mexico.
Trirachodon is an extinct genus of cynodonts. Fossils have been found in the Cynognathus Assemblage Zone of the Beaufort Group in South Africa and the Omingonde Formation of Namibia, dating back to the Early and Middle Triassic.
Tuditanomorpha is a suborder of microsaur lepospondyls. 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.
Nannaroter is an extinct genus of Recumbirostran tetrapod within the family Ostodolepidae.
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.
Proxilodon is an extinct genus of recumbirostran microsaur from the Early Permian Speiser Formation of Kansas, United States. It contains a single species, Proxilodon bonneri,.
Aletrimyti is an extinct monotypic genus of recumbirostran tetrapod from the Early Permian of Oklahoma.
