Seymouriamorpha

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Seymouriamorpha
Seymouria1.jpg
Fossil of Seymouria in the National Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
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]

Contents

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. [3]

They have been considered to be the makers of the trace fossils placed in the ichnogenus Amphisauropus . [4]

Taxonomy

Cladogram based on Ruta, Jeffery, & Coates (2003): [6]

Seymouriamorpha

Cladogram based on Klembara (2009) & Klembara (2010): [7] [8]

Seymouriamorpha

References

  1. ↑ 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 .
  2. ↑ Laurin, Michel (2010). How Vertebrates Left the Water. Berkeley: University of California Press. ISBN   978-0-520-26647-6.
  3. ↑ Bulanov VV (2003). "Evolution and systematics of seymouriamorph parareptiles". Paleontological Journal. 37 (Supplement 1): 1–105.
  4. ↑ Marchetti, Lorenzo; Mujal, Eudald; Bernardi, Massimo (January 2017). "An unusual Amphisauropus trackway and its implication for understanding seymouriamorph locomotion". Lethaia. 50 (1): 162–174. Bibcode:2017Letha..50..162M. doi:10.1111/let.12184.
  5. ↑ Olson, E. C. (1951). "Fauna of upper Vale and Choza: 1-5" (PDF). Fieldiana Geology. 10 (11): 89–128. doi: 10.5962/bhl.title.3264 .
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ Klembara, Jozef (2011). "The cranial anatomy, ontogeny, and relationships of Karpinskiosaurus secundus (Amalitzky) (Seymouriamorpha, Karpinskiosauridae) from the Upper Permian of European Russia" (PDF). Zoological Journal of the Linnean Society. 161 (1): 184–212. doi: 10.1111/j.1096-3642.2009.00629.x .
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