Nothosaur
extinct order of Mesozoic marine reptiles
Nothosaurs (superfamily Nothosauroidea) were Triassic marine sauropterygian reptiles. They averaged about 3 metres (10 ft) in length, with a long body and tail. The feet were paddle-like, and are known to have been webbed in life, to help power the animal when swimming. The neck was quite long, and the head was elongated and flattened, and relatively small in relation to the body. The margins of the long jaws were equipped with numerous sharp outward-pointing teeth, indicating a diet of fish and squid.
Taxonomy
The Nothosauroidea has been suggested to consist of two suborders, the Pachypleurosauria, which are small primitive forms, and the Nothosauria (including two families Nothosauridae and Simosauridae), which may have evolved from pachypleurosaurs.
The relation of pachypleurosaurs to Nothosauroidea is uncertain, as several analyses recover the clade as basal to Eusauropterygia, e.i. the clade formed by Nothosauria and Pistosauroidea, instead as the sister taxon of Nothosauria. Many recent analyses have recovered the pachypleurosaurs as a basal clade of eosauropterygians outside of the nothosauroidea.
Nothosaur-like reptiles were in turn ancestral to the more completely marine plesiosaurs, which replaced them at the end of the Triassic period.
The public source identifies “Nothosaur” as extinct order of Mesozoic marine reptiles. This brief keeps that definition visible, then builds a research path around Nothosaur, extinct and order.
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This entry incorporates text from “Nothosaur” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.