Last updated

Temporal range: Permian
Tseajaia BW.jpg
Tseajaia life reconstruction
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Order: Diadectomorpha
Family: Tseajaiidae
Genus: Tseajaia
Vaughn, 1964

Tseajaia is an extinct genus of tetrapod. It was a basal diadectomorph that lived in the Permian of North America. [1] The skeleton is that of a medium-sized, rather advanced reptile-like amphibian. In life it was about 1 metre (3 ft) long and may have looked vaguely like an iguana, though slower and with a more amphibian foot without claws. The dentition was somewhat blunt, indicating herbivory or possibly omnivory.



Tseajaia was described from a single, fairly complete specimen and was given its own family by Robert L. Carroll. It was originally thought to be a Seymouriamorph. [2] Additional finds allowing for a better taxonomic analysis indicate they belong in the Diadectomorpha, as the sister group to the large and more derived Diadectidae. Tseajaia itself being a fairly generalized form, gives a reasonable indication of the build and looks of the closest relatives of the amniotes. [3] [4]

Related Research Articles

Labyrinthodontia Subclass of early amphibious tetrapods

Labyrinthodontia is an extinct amphibian subclass, which constituted some of the dominant animals of late Paleozoic and early Mesozoic eras. The group evolved from lobe-finned fishes in the Devonian and is ancestral to all extant landliving vertebrates. As such it constitutes an evolutionary grade rather than a natural group (clade). The name describes the pattern of infolding of the dentin and enamel of the teeth, which are often the only part of the creatures that fossilize. They are also distinguished by a heavily armoured skull roof, and complex vertebrae, the structure of which were used in older classifications of the group.

Lepospondyli Extinct subclass of amphibians

Lepospondyli is a diverse taxon of amphibian tetrapods. With the exception of one late-surviving lepospondyl from the Late Permian of Morocco, lepospondyls lived from the Early Carboniferous (Mississippian) to the Early Permian and were geographically restricted to what is now Europe and North America. Five major groups of lepospondyls are known: Adelospondyli; Aïstopoda; Lysorophia; Microsauria; and Nectridea. Lepospondyls have a diverse range of body forms and include species with newt-like, eel- or snake-like, and lizard-like forms. Various species were aquatic, semiaquatic, or terrestrial. None were large, and they are assumed to have lived in specialized ecological niches not taken by the more numerous temnospondyl amphibians that coexisted with them in the Paleozoic. Lepospondyli was named in 1888 by Karl Alfred von Zittel, who coined the name to include some tetrapods from the Paleozoic, that shared some specific characteristics in the notochord and teeth. Lepospondyls have sometimes been considered to be either related or ancestral to modern amphibians or to Amniota.


Reptiliomorpha is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was defined by Michel Laurin (2001) and Vallin and Laurin (2004) as the largest clade that includes Homo sapiens, but not Ascaphus truei.


Anthracosauria is an order of extinct reptile-like amphibians that flourished during the Carboniferous and early Permian periods, although precisely which species are included depends on one's definition of the taxon. "Anthracosauria" is sometimes used to refer to all tetrapods more closely related to amniotes such as reptiles, mammals, and birds, rather than lissamphibians such as frogs and salamanders. An equivalent term to this definition would be Reptiliomorpha. Anthracosauria has also been used to refer to a smaller group of large, crocodilian-like aquatic tetrapods also known as embolomeres.


Diadectes is an extinct genus of large reptiliomorphs that lived during the early Permian period. Diadectes was one of the first herbivorous tetrapods, and also one of the first fully terrestrial animals to attain large size.


Diadectidae is an extinct family of early tetrapods that lived in what is now North America and Europe during the Late Carboniferous and Early Permian, and in Asia during the Late Permian. They were the first herbivorous tetrapods, and also the first fully terrestrial animals to attain large sizes. Footprints indicate that diadectids walked with an erect posture. They were the first to exploit plant material in terrestrial food chains, making their appearance an important stage in both vertebrate evolution and the development of terrestrial ecosystems.


Diadectomorpha are a clade of large tetrapods that lived in Euramerica during the Carboniferous and Early Permian periods and in Asia during Late Permian (Wuchiapingian), They have typically been classified as advanced reptiliomorphs close to the ancestry of the Amniota, though some paleontologists consider them basal synapsids. They include both large carnivorous and even larger herbivorous forms, some semi-aquatic and others fully terrestrial. The Diadectomorpha seem to have evolved during late Mississippian times, although they only became common after the Carboniferous rainforest collapse and flourished during the Late Pennsylvanian and Early Permian periods.

Nectridea Extinct order of amphibians

Nectridea is the name of an extinct order of lepospondyl tetrapods from the Carboniferous and Permian periods, including animals such as Diplocaulus. In appearance, they would have resembled modern newts or aquatic salamanders, although they are not close relatives of modern amphibians. They were characterized by long, flattened tails to aid in swimming, as well as numerous features of the vertebrae.

<i>Parotosuchus</i> Extinct genus of amphibians

Parotosuchus is an extinct genus of capitosaurian temnospondyl amphibians within the family Mastodonsauridae. Fossils are known from the Early Triassic of Europe, Africa, Australia, and Antarctica. It was about 2 metres (6.6 ft) long and likely lived in aquatic environments such as lakes and rivers. Parotosuchus was covered in a scaly skin, unlike the smooth skin of modern-day amphibians, and probably moved with an eel-like motion in the water.

<i>Limnoscelis</i> Genus of diadectomorphs

Limnoscelis was a genus of large diadectomorph tetrapods from the Late Carboniferous of western North America. It includes two species: the type species Limnoscelis paludis from New Mexico, and Limnoscelis dynatis from Colorado, both of which are thought to have lived concurrently. No specimens of Limnoscelis are known from outside of North America. Limnoscelis was carnivorous, and likely semiaquatic, though it may have spent a significant portion of its life on land. Limnoscelis had a combination of derived amphibian and primitive reptilian features, and its placement relative to Amniota has significant implications regarding the origins of the first amniotes.


Gephyrostegus is an extinct genus of gephyrostegid reptiliomorph amphibian. It was a small animal, 22 cm in total length, of generally lizard-like build and presumably habit. It had large eyes and a large number of small, pointed teeth, indicating it was an active insectivorous hunter. The remains have been found in Nýřany, Czech Republic, dating from around 310 million years ago.

<i>Orobates</i> Extinct genus of reptiliomorphs

Orobates is an extinct genus of diadectid. It lived in the middle Permian, about 260 million years ago. Its remains were found in Germany. A combination of primitive and derived traits distinguish it from all other well-known members of the Diadectidae, a family of herbivorous reptile-like amphibians. It weighed about 4 kg and appears to have been part of an upland fauna, browsing on high fibre plants.

Limnoscelidae Extinct family of amphibians

Limnoscelidae is a family of carnivorous diadectomorphs. They would have been the largest terrestrial carnivores of their day, the other large carnivores being aquatic or semi aquatic labyrinthodont amphibians. The Limnoscelidae themselves, being close to the ancestry of amniotes, would have been well adapted land animals, but still dependent on anamniote eggs, and possibly having a tadpole stage. Contrary to the more advanced herbivorous diadectids, the teeth retained labyrinthodont infolding of the enamel, and were pointed and slightly recurved at the tip.

Oradectes is an extinct genus of diadectid reptiliomorph. It is known from a single partial skeleton collected from the Early Permian Cutler Formation of Colorado in the United States. The type species, O. sanmiguelensis, was originally named as a species of Diadectes in 1965. It was given its own genus in 2010.

Phanerosaurus is an extinct genus of diadectid reptiliomorph from the Early Permian of Germany. Fossils are known from the Leukersdorf Formation near Zwickau. German paleontologist Christian Erich Hermann von Meyer named the type species P. naumanni in 1860 on the basis of several sacral and presacral vertebrae. A second species, P. pungnax, was named in 1882 but placed in its own genus Stephanospondylus in 1905.

Desmatodon is an extinct genus of diadectid reptiliomorph. With fossils found from the Kasimovian (Missourian) stage of the Late Carboniferous of Pennsylvania, Colorado, and New Mexico in the United States, Desmatodon is the oldest known diadectid. Two species are currently recognized: the type species D. hollandi and the species D. hesperis.

<i>Stephanospondylus</i> Extinct genus of amphibians

Stephanospondylus is an extinct genus of diadectid reptiliomorph from the Early Permian of Germany. Fossils have been found in deposits of the Lower Rotliegend near Dresden. The type species S. pugnax was originally referred to the genus Phanerosaurus in 1882 but was placed in its own genus in 1905.

Tambach Formation

The Tambach Formation is an Early Permian-age geologic formation in central Germany. It consists of red to brown-colored sedimentary rocks such as conglomerate, sandstone, and mudstone, and is the oldest portion of the Upper Rotliegend within the Thuringian Forest Basin.


  1. Time Traveler: In Search of Dinosaurs and Other Fossils from Montana to Mongolia by Michael Novacek
  2. Moss, J.L. (1972): The morphology and phylogenetic relationships of the Lower Permian tetrapod Tseajaia campi Vaughn (Amphibia: Seymouriamorpha). University of California Publications in Geological Sciences, vol 98, pp 1-72.
  3. Kissel, R. (2010). Morphology, Phylogeny, and Evolution of Diadectidae (Cotylosauria: Diadectomorpha). Toronto: University of Toronto Press. p. 185. hdl:1807/24357.
  4. Berman, D.S, Sumida, S.S., and Lombard, R.E. (1992): Reinterpretation of the temporal and occipital regions in Diadectes and the relationship of diadectomorphs. Journal of Paleontology no 66: pp 481–499.