Seymouriamorpha

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Seymouriamorpha
Temporal range: Early Permian - Late Permian
Seymouria1.jpg
Skeleton of Seymouria in the National Museum of Natural History
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Reptiliomorpha
Order: Seymouriamorpha
Watson, 1917

Seymouriamorpha were a small but widespread group of limbed vertebrates (tetrapods). They have long been considered reptiliomorphs, and most paleontologists may still accept this point of view, but some analyses suggest that seymouriamorphs are stem-tetrapods (not more closely related to Amniota than to Lissamphibia).[1] 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. The adults were terrestrial. They ranged from lizard-sized creatures (30 centimeters) to crocodile-sized 150 centimeter long animals. They were reptile-like. 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 Permian.[2]

Taxonomy[edit]

Cladogram based on Ruta, Jeffery, & Coates (2003):[4]

Seymouriamorpha

Kotlassia




Utegenia





Seymouria baylorensis



Seymouria sanjuanensis





Ariekanerpeton




Discosauriscus austriacus



Discosauriscus pulcherrimus







Cladogram based on Klembara (2009) & Klembara (2010):[5][6]

Seymouriamorpha

Utegenia




Seymouria




Karpinskiosaurus


Discosauriscidae


Makowskia



Spinarerpeton





Ariekanerpeton



Discosauriscus







Gallery[edit]

References[edit]

  1. ^ Laurin, Michel (2010). How Vertebrates Left the Water. Berkeley: University of California Press. ISBN 978-0-520-26647-6. 
  2. ^ Bulanov, V. V. (2003). "Evolution and systematics of seymouriamorph parareptiles". Paleontological Journal 37 (Supplement 1): 1–105. 
  3. ^ Olson, E. C. (1951). "Fauna of upper Vale and Choza: 1-5". Fieldiana Geology 10 (11): 89–128. doi:10.5962/bhl.title.3264. 
  4. ^ Ruta, M.; Jeffery, J. E.; Coates, M. I. (2003). "A supertree of early tetrapods". Proceedings of the Royal Society B 270 (1532): 2507–16. doi:10.1098/rspb.2003.2524. PMC 1691537. PMID 14667343. 
  5. ^ Klembara, Jozef (2009). "The skeletal anatomy and relationships of a new discosauriscid seymouriamorph from the lower Permian of Moravia (Czech Republic)". Annals of Carnegie Museum 77 (4): 451–483. doi:10.2992/0097-4463-77.4.451. 
  6. ^ Klembara, Jozef (2011). "The cranial anatomy, ontogeny, and relationships of Karpinskiosaurus secundus (Amalitzky) (Seymouriamorpha, Karpinskiosauridae) from the Upper Permian of European Russia". Zoological Journal of the Linnean Society 161 (1): 184–212. doi:10.1111/j.1096-3642.2009.00629.x. 

External links[edit]