page_title: Temnospondyli
section_title: Classification
hierarchical_section_title: Temnospondyli / Classification
caption_attribution_description: Zygosaurus lucius
context_page_description: Temnospondyli is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few species continued into the Cretaceous. Fossils have been found on every continent. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including fresh water, 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 considered amphibians, many had characteristics, such as scales, claws, and armour-like bony plates, that distinguish them from modern amphibians.
  Temnospondyls have been known since the early 19th century, and were initially thought to be reptiles. They were described at various times as batrachians, stegocephalians, and labyrinthodonts, although these names are now rarely used.
context_section_description: Originally, temnospondyls were classified according to the structure of their vertebrae. Early forms, with complex vertebrae consisting of a number of separate elements, were placed in the suborder Rachitomi, and large Triassic aquatic forms with simpler vertebrae were placed in the suborder Stereospondyli. With the recent growth of phylogenetics, this classification is no longer viable. The basic rhachitomous condition is found in many primitive tetrapods, and is not unique to one group of temnospondyls. Moreover, the distinction between rhachitomous and stereospondylous vertebrae is not entirely clear. Some temnospondyls have rhachitomous, semirhachitomous, and sterospondylous vertebrae at different points in the same vertebral column. Other taxa have intermediate morphologies that do not fit into any category. Rachitomi is no longer recognized as a group, but Stereospondyli is still considered valid. Below is a simplified taxonomy of temnospondyls showing currently recognized groups:
  Class Amphibia
  Order Temnospondyli
  Superfamily Edopoidea
  Family Cochleosauridae (Chenoprosopidae)
  Family Edopidae
  Family Dendrerpetontidae
  Suborder Euskelia
  Superfamily Dissorophoidea
  Family Amphibamidae
  Family Branchiosauridae
  Family Dissorophidae
  Family Micromelerpetontidae
  Superfamily Eryopoidea
  Family Eryopidae
  Family Parioxyidae
  Family Zatrachydidae
  Clade Limnarchia
  Clade Stereospondylomorpha
  Superfamily Archegosauroidea
  Family Actinodontidae
  Family Archegosauridae
  Family Intasuchidae (placement is uncertain)
  Family Sclerocephalidae
  Suborder Stereospondyli
  Family Peltobatrachidae
  Family Lapillopsidae
  Family Rhinesuchidae
  Family Lydekkerinidae
  Clade Capitosauria
  Superfamily Mastodonsauroidea (Capitosauroidea)
  Family Heylerosauridae
  Family Mastodonsauridae
  Family Stenotosauridae
  Infraorder Trematosauria
  Superfamily Trematosauroidea
  Superfamily Metoposauroidea
  Superfamily Plagiosauroidea
  Superfamily Brachyopoidea
  Superfamily Rhytidosteoidea
caption: Zygosaurus, a dissorophid euskelian
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