Stereospondylomorpha

Archegosaurus is a genus of temnospondyl amphibian which lived during the Asselian to Wuchiapingian stages of the Permian, around 299-253 million years ago. The remains of this animal, consisting of at least 90 partial skeletons (mostly skulls), have been found in Germany. The name Archegosaurus was coined by Goldfuss in 1847. Archegosaurus is a member of Archegosauridae and is that family's type genus.

Archegosauridae is a family of relatively large and long snouted temnospondyls that lived in the Permian period. They were fully aquatic animals, and were metabolically and physiologically more similar to fish than modern amphibians. The family has been divided into two subfamilies, the longer-snouted Platyoposaurinae and the shorter-snouted Melosaurinae.

Sclerocephalus is an extinct genus of temnospondyl amphibian from the lowermost Permian of Germany and Czech Republic with four valid species, including the type species S. haeuseri. It is one of the most completely preserved and most abundant Palaeozoic tetrapods. Sclerocephalus was once thought to be closely related to eryopoid temnospondyls, but it is now thought to be more closely related to archegosauroids. It is the only genus in the family Sclerocephalidae.

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 paraphy

Archegosauroidea is an extinct superfamily of Permian temnospondyls. The superfamily is assigned to the clade Stereospondylomorpha and is the sister taxon to the suborder Stereospondyli. It includes the families Actinodontidae and Archegosauridae, and possibly the genus Intasuchus, which is placed within the monotypic family Intasuchidae. They were fully aquatic animals, and were metabolically and physiologically more similar to fish than modern amphibians.

Melosaurus is an extinct genus of temnospondyl amphibian. Fossils of it have been found in Russia. Fossil remains of Melosaurus uralensis were discovered at Belebei in Russia. Its fossils dated of the Asselian-Olenekian stages (299–245 million years ago). Fossils of Melosaurus sp. were also unearthed at the site. Fossils of Melosaurus uralensis were found at the Sterlitamak site in Bashkortostan in Russia. The span of the strata is listed as Wordian (268–265.8 million years ago).