Temnospondyli or temnospondyls is a diverse ancient order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian and Triassic periods, with fossils being found on every continent. A few species continued into the Jurassic and Early Cretaceous periods, but all had gone extinct by the Late Cretaceous. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are amphibians, many had characteristics such as scales and armour-like bony plates that distinguish them from the modern soft-bodied lissamphibians.
Trematosauria is one of two major groups of temnospondyl amphibians that survived the Permian-Triassic extinction event, the other being the Capitosauria. The trematosaurs were a diverse and important group that included many medium-sized to large forms that were semi-aquatic to fully aquatic. The group included long-snouted forms such as the trematosauroids and short, broad-headed forms such as the metoposaurs. Although most groups did not survive beyond the Triassic, one lineage, the brachyopoids, continued until the Cretaceous period. Trematosauria is defined as all stereospondyls more closely related to Trematosaurus than to Parotosuchus, a capitosaurian.
Metoposaurus meaning "front lizard" is an extinct genus of stereospondyl temnospondyl amphibian, known from the Late Triassic of Germany, Italy, Poland, and Portugal. This mostly aquatic animal possessed small, weak limbs, sharp teeth, and a large, flat head. This highly flattened creature mainly fed on fish, which it captured with its wide jaws lined with needle-like teeth. Many Metoposaurus mass graves have been found, probably from creatures that grouped together in drying pools during drought.
The Stereospondyli are a group of extinct temnospondyl amphibians that existed primarily during the Mesozoic period. They are known from all seven continents and were common components of many Triassic ecosystems, likely filling a similar ecological niche to modern crocodilians prior to the diversification of pseudosuchian archosaurs.
Cyclotosaurus is an extinct genus of temnospondyl within the family Mastodonsauridae. It was of great size for an amphibian, had an elongated skull up to 56 cm (22 in).
Siderops is an extinct genus of chigutisaurid temnospondyl from Early Jurassic of Australia, containing the species S. kehli.
Eocyclotosaurus is an extinct genus of mastodonsauroid temnospondyl from the Middle Triassic (Anisian). The name Eocyclotosaurus means "dawn round-eared lizard". It is characterized as a capitosauroid with a long and slender snout, closed otic fenestra, and small orbits. It measured over one metre and had a 22 cm skull.
Rhytidosteidae is a family of Temnospondyli that lived in the Permian and Triassic.
Brachyopoidea is a superfamily of temnospondyls that lived during the Mesozoic. It contains the families Brachyopidae and Chigutisauridae. The earliest records of brachyopids are from the Lower Triassic in Australia. The latest-surviving member of the superfamily is the chigutisaurid Koolasuchus from the Early Cretaceous of Australia.
Metoposauridae is an extinct family of trematosaurian temnospondyls. The family is known from the Triassic period. Most members are large, approximately 1.5 metres (4.9 ft) long and could reach 3 m long. Metoposaurids can be distinguished from the very similar mastodonsauroids by the position of their eyes, placed far forward on the snout.
The Mastodonsauroidea are an extinct superfamily of temnospondyl amphibians known from the Triassic. Fossils belonging to this superfamily have been found in North America, Greenland, Europe, Asia, and Australia. Ferganobatrachus from the Jurassic of Asia was initially assigned to this superfamily, but is now considered to be congeneric with the brachyopid Gobiops.
Stereospondylomorpha is a clade of temnospondyls. It includes the superfamily Archegosauroidea and the more diverse group Stereospondyli. Stereospondylomorpha was first proposed by Yates and Warren (2000), who found Archegosauroidea and Stereospondyli to be sister taxa in their phylogenetic analysis. A similar clade is Archegosauriformes, named by Schoch and Milner (2000), which includes Stereospondyli and some Permian temnospondyls that are similar in appearance to stereospondyls, including the archegosauroids. However, according to Schoch and Milner's phylogeny, Archegosauroidea is a paraphyletic group of taxa that are successively basal to Stereospondyli, rather than a monophyletic sister taxon.
Almasaurus is an extinct genus of trematosaurian temnospondyl within the family Latiscopidae. It is known from several skulls and some postcranial material found from the Argana Formation in Morocco, which dates back to the Late Triassic.
Cosgriffius is an extinct genus of trematosaurian temnospondyl within the family Trematosauridae. It was described in 1993 by Samuel P. Welles based on a single partial skull from the well-known Meteor Crater Quarry in Arizona that also produced more abundant remains of the capitosaur Wellesaurus peabodyi. The skull was long and slender, features typically associated with the trematosaurid subfamily Lonchorhynchinae. This is the only trematosaurid known from western North America.
Wellesaurus is an extinct genus of mastodonsauroid temnospondyl. They were amphibious carnivores that lived in freshwater environments.
Stanocephalosaurus is an extinct genus of large-sized temnospondyls living through the early to mid Triassic. The etymology of its name most likely came from its long narrow skull when compared to other temnospondyls. Stanocephalosaurus lived an aquatic lifestyle, with some species even living in salt lakes. There are currently three recognized species and another that needs further material to establish its legitimacy. The three known species are Stanocephalosaurus pronus from the Middle Triassic in Tanzania, Stanocephalosaurus amenasensis from the Lower Triassic in Algeria, and Stanocephalosaurus birdi, from the middle Triassic in Arizona. Stanocephalosaurus rajareddyi from the Middle Triassic in central India needs further evidence in order to establish its relationship among other Stanocephalosaurs. Like other temnospondyls, Stanocephalosaurus was an aquatic carnivore. Evidence of multiple species discovered in a wide range of localities proves that Stanocephalosaurus were present all across Pangea throughout the early to mid Triassic.
Capitosauria is an extinct group of large temnospondyl amphibians with simplified stereospondyl vertebrae. Mainly living as piscivores in lakes and rivers, the Capitosauria and its sister taxon Trematosauria were the only major labyrinthodonts that existed during the Mesozoic in ecological niches broadly similar to those of modern crocodiles, and some grew to very large sizes. At 6 meters in length, the Mid-Triassic Mastodonsaurus giganteus is not only thought to have been the largest capitosaur, but possibly also the largest amphibian to have lived. The latest known remains are from the Rhaetian of Germany and are referred to Cyclotosaurus.
Uruyiella is an extinct genus of laidleriid temnospondyl from Late Triassic Buena Vista Formation of Uruguay. It was first named by Graciela Piñeiro, Claudia Marsicano and Nora Lorenzo in 2007, from a nearly complete skull. The type species is Uruyiella liminea and it is the only close relative of the enigmatic Early Triassic Laidleria.
Meyerosuchus is an extinct genus of mastodonsauroidean temnospondyl. Fossils have been found from the Early Triassic Hardegsen Formation in southern Germany. Meyerosuchus is present in late Olenekian deposits of the Middle Buntsandstein. The type species M. fuerstenberganus was named in 1966, although remains have been known since 1855. Meyerosuchus is closely related to Stenotosaurus; both genera are grouped in the family Stenotosauridae and the two genera may even be synonymous.
Callistomordax is an extinct genus of temnospondyl amphibian from the Middle Triassic of Germany. The type and only species, Callistomordax kugleri, was named in 2008. It is known from several well-preserved skeletons found in the Erfurt Formation, part of the Lower Keuper, which dates back to the late Ladinian stage.
