Temporal range: Late Carboniferous[1] - Late Permian
Fossil of Seymouria in the National Museum of Natural History
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Clade:
Reptiliomorpha (?)
Order:
†Seymouriamorpha Watson, 1917
Subgroups
See text.
Seymouriamorpha were a small but widespread group of limbed vertebrates (tetrapods). They have long been considered stem-amniotes (reptiliomorphs), and most paleontologists still accept this point of view, but some analyses suggest that seymouriamorphs are stem-tetrapods (not more closely related to Amniota than to Lissamphibia).[2] Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larvae bearing external gills and grooves from the lateral line system have been found, making them unquestionably amphibians. Though as they matured, they became more terrestrial and reptile-like. They ranged from 30 cm (1 ft) long lizard-sized creatures to the 1.5 m (5 ft) long Enosuchus. If seymouriamorphs are reptiliomorphs, they were the distant relatives of amniotes. Seymouriamorphs form into three main groups, Kotlassiidae, Discosauriscidae, and Seymouriidae, a group that includes the best known genus, Seymouria. The last seymouriamorph became extinct by the end of the Permian.[3]
^Klembara, J.; Werneburg, R.; Mikudíková, M.; Šurka, J.; Štamberg, S. (2023). "The oldest records of the stem amniote Discosauriscus (Seymouriamorpha, Discosauriscidae) from the European Carboniferous-Permian boundary". Bulletin of Geosciences. 98 (3): 233–246. doi:10.3140/bull.geosci.1882.
^Laurin, Michel (2010). How Vertebrates Left the Water. Berkeley: University of California Press. ISBN 978-0-520-26647-6.
^Bulanov VV (2003). "Evolution and systematics of seymouriamorph parareptiles". Paleontological Journal. 37 (Supplement 1): 1–105.
Seymouriamorpha were a small but widespread group of limbed vertebrates (tetrapods). They have long been considered stem-amniotes (reptiliomorphs), and...
containing anthracosaurs and amniotes. Säve-Söderbergh subsequently added Seymouriamorpha to his Reptiliomorpha as well. Alfred Sherwood Romer rejected Säve-Söderbergh's...
Paleozoic tetrapods, such as Temnospondyli, Lepospondyli, Embolomeri, and Seymouriamorpha. Most scientists have concluded that all of the primary groups of modern...
Discosauriscus, which was a close relative of Seymouria in the group Seymouriamorpha. This shows that seymouriamorphs (including Seymouria) had a larval...
groups include Embolomeri (Late Paleozoic large aquatic predators), Seymouriamorpha (semiaquatic to terrestrial Permian forms related to amniotes), among...
Furrow, in the Czech Republic. Discosauriscus belongs to the order Seymouriamorpha, and is the type genus of the family Discosauriscidae. Currently recognised...
Family Archeriidae Order Gephyrostegida Family Gephyrostegidae Order Seymouriamorpha Family Discosauriscidae Order Diadectomorpha Family Limnoscelididae...
mostly aquatic, the first highly terrestrially adapted groups being the Seymouriamorpha and the Diadectomorpha. The seymouriamorphs were small to medium-sized...
been allied with the family Kotlassiidae, which is within the order Seymouriamorpha. It has been highly debated where exactly the Kotlassia falls into...
Family Archeriidae Family Chroniosuchidae Family Bystrowianidae Order Seymouriamorpha Family Seymouriidae Family Discosauriscidae Family Kotlassiidae Orders/Suborders...
build like those found in the amphibian reptiliomorph groups like Seymouriamorpha and Diadectomorpha, Casineria also shows features that tie it in with...
relationships of the Lower Permian tetrapod Tseajaia campi Vaughn (Amphibia: Seymouriamorpha). University of California Publications in Geological Sciences, vol...
Originally described by Vaughn, this animal was first assigned to the group Seymouriamorpha, however, upon reassessment of the holotype it was demonstrated to...
order within the superorder Reptiliomorpha, along with the orders Seymouriamorpha and Diadectomorpha, thus making the Anthracosaurians the "lower" reptile-like...
ontogeny, and relationships of Karpinskiosaurus secundus (Amalitzky) (Seymouriamorpha, Karpinskiosauridae) from the Upper Permian of European Russia". Zoological...
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