Seymouriamorpha

Seymouriamorpha
Temporal range: Early Permian - Late Permian
Skeleton of Seymouria in the National Museum of Natural History
Scientific classification
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 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

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







References

  1. ↑ Laurin, Michel (2010). How Vertebrates Left the Water. Berkeley: University of California Press. ISBN 978-0-520-26647-6.
  2. ↑ Bulanov VV (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 1691537Freely accessible. 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.
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