{{Short description|Extinct order of tetrapodomorphs}} {{Automatic taxobox | fossil_range = Late Carboniferous<ref>{{Cite journal|last1=Klembara |first1=J. |last2=Werneburg |first2=R. |last3=Mikudíková |first3=M. |last4=Šurka |first4=J. |last5=Štamberg |first5=S. |title=The oldest records of the stem amniote ''Discosauriscus'' (Seymouriamorpha, Discosauriscidae) from the European Carboniferous-Permian boundary |year=2023 |journal=Bulletin of Geosciences |volume=98 |issue=3 |pages=233–246 |doi=10.3140/bull.geosci.1882 |doi-access=free }}</ref> - Late Permian | image = Seymouria1.jpg | image_caption = Fossil of ''Seymouria'' in the National Museum of Natural History | taxon = Seymouriamorpha | authority = Watson, 1917 | subdivision_ranks = Subgroups | subdivision = 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).<ref name=L10>{{cite book|last=Laurin|first=Michel |title=How Vertebrates Left the Water|year=2010|publisher=University of California Press|location=Berkeley|isbn=978-0-520-26647-6}}</ref>
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 non-amniotes. 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 are divided into three main groups: Kotlassiidae, Discosauriscidae, and Seymouriidae, which includes the best-known genus, ''Seymouria''. The last seymouriamorphs became extinct by the end of the Permian.<ref name=Bu03>{{cite journal | last1 = Bulanov | first1 = V. V. |name-list-style=vanc | year = 2003 | title = Evolution and systematics of seymouriamorph parareptiles | journal = Paleontological Journal | volume = 37 | issue = Supplement 1 | pages = 1–105}}</ref>
They have been considered to be the makers of the trace fossils placed in the ichnogenus ''Amphisauropus''.<ref name=MarMujBer17>{{cite journal |last1=Marchetti |first1=Lorenzo |last2=Mujal |first2=Eudald |last3=Bernardi |first3=Massimo |title=An unusual ''Amphisauropus'' trackway and its implication for understanding seymouriamorph locomotion |journal=Lethaia |date=January 2017 |volume=50 |issue=1 |pages=162–174 |doi=10.1111/let.12184|bibcode=2017Letha..50..162M }}</ref>
==Taxonomy== *''Biarmica'' *''Enosuchus'' *''Kotlassia'' *''Leptoropha'' *''Microphon'' *''Nyctiboetus'' *''Utegenia'' *''Waggoneria''<ref name=Olson>{{cite journal |last=Olson |first=E. C. |year=1951 |title=Fauna of upper Vale and Choza: 1-5 |journal=Fieldiana Geology |volume=10 |issue=11 |pages=89–128 |doi=10.5962/bhl.title.3264|url=https://www.archive.org/download/faunaofuppervale1011olso/faunaofuppervale1011olso.pdf |doi-access=free }}</ref> *Family '''Karpinskiosauridae''' **''Karpinskiosaurus'' *Family '''Discosauriscidae''' **''Ariekanerpeton'' **''Discosauriscus'' **''Makowskia'' **''Spinarerpeton'' *Family '''Seymouriidae''' **''Seymouria''
Cladogram based on Ruta, Jeffery, & Coates (2003):<ref name=RJC03>{{cite journal |last=Ruta |first=M. |author2=Jeffery, J. E. |author3= Coates, M. I. |year=2003 |title=A supertree of early tetrapods |journal=Proceedings of the Royal Society B |volume=270 |pages=2507–16 |pmid=14667343 |issue=1532 |doi=10.1098/rspb.2003.2524 |pmc=1691537}}</ref>
{{clade| style=font-size:100%;line-height:85% |label1='''Seymouriamorpha''' |1={{clade |1=''Kotlassia'' |2={{clade |1=''Utegenia'' |2={{clade |1={{clade |1=''Seymouria baylorensis'' |2=''Seymouria sanjuanensis'' }} |2={{clade |1=''Ariekanerpeton'' |2={{clade |1=''Discosauriscus austriacus'' |2=''Discosauriscus pulcherrimus'' }} }} }} }} }} }}
Cladogram based on Klembara (2009) & Klembara (2010):<ref name=Klembara2009>{{cite journal |last=Klembara |first=Jozef |year=2009 |title=The skeletal anatomy and relationships of a new discosauriscid seymouriamorph from the lower Permian of Moravia (Czech Republic) |journal=Annals of Carnegie Museum |volume=77 |issue=4 |pages=451–483 |doi=10.2992/0097-4463-77.4.451}}</ref><ref name=Klembara2010>{{cite journal |last=Klembara |first=Jozef |year=2011 |title=The cranial anatomy, ontogeny, and relationships of Karpinskiosaurus secundus (Amalitzky) (Seymouriamorpha, Karpinskiosauridae) from the Upper Permian of European Russia |journal=Zoological Journal of the Linnean Society |volume=161 |issue=1 |pages=184–212 |doi=10.1111/j.1096-3642.2009.00629.x|doi-access=free |url=https://zenodo.org/records/846896/files/article.pdf }}</ref>
{{clade| style=font-size:100%;line-height:85% |label1='''Seymouriamorpha''' |1={{clade |1=''Utegenia'' |2={{clade |1=''Seymouria'' |2={{clade |1=''Karpinskiosaurus'' |label2=Discosauriscidae |2={{clade |1={{clade |1=''Makowskia'' |2=''Spinarerpeton'' }} |2={{clade |1=''Ariekanerpeton'' |2=''Discosauriscus'' }} }} }} }} }} }}
==Gallery== <gallery> File:Kotlassia prima1DB.jpg|''Kotlassia'' File:Karpinskiosaurus1DB.jpg|''Karpinskiosaurus'' </gallery>
==References== {{Reflist}}
==External links== * [http://bulletin.geoscienceworld.org/cgi/content/abstract/55/4/379 Bystrow, A.P. ''Kotlassia prima'' Amalitzky. Bulletin of the Geological Society of America, Washington, 1944, v.55, N5, pp.379-416.] * [https://web.archive.org/web/20050409172919/http://www.palaeos.com/vertebrates/Units/190Reptilomorpha/190.300.html Seymouriamorpha] - at Paleos * [http://www.tol.tolweb.org/Seymouriamorpha/15005 Seymouriamorpha] at Tree of Life Web Project
{{Reptiliomorpha}} {{Taxonbar|from=Q134777}}
Category:Seymouriamorpha Category:Pennsylvanian first appearances Category:Lopingian extinctions Category:Prehistoric tetrapod orders