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Pachypleurosaurs facts for kids

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Pachypleurosaurs
Temporal range: Induan-Carnian, 251–227Ma
Keichousaurus BW.jpg
Keichousaurus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Sauropterygia
Clade: Eosauropterygia
Suborder: Pachypleurosauria
Nopcsa, 1928
Genera
  • Diandongosaurus
  • Hanosaurus
  • Honghesaurus
  • Majiashanosaurus
  • Qianxisaurus
  • Wumengosaurus
  • Keichousauridae
    • Dianopachysaurus
    • Keichousaurus
  • Pachypleurosauridae
    • Anarosaurus
    • Dactylosaurus
    • Luopingosaurus
    • Neusticosaurus
    • Odoiporosaurus
    • Prosantosaurus
    • Serpianosaurus
Pachypleurosaurus
Pachypleurosaurus

Pachypleurosauria is an extinct clade of primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from 0.2–1 metre (0.66–3.28 ft), with small heads, long necks, paddle-like limbs, and long, deep tails. The limb girdles are greatly reduced, so it is unlikely these animals could move about on land. The widely spaced peg-like teeth project at the front of the jaws, indicating that these animals fed on fish. In the species Prosantosaurus, it was observed that they fed on small fishes and crustaceans which they devoured entirely and that its teeth regrew after they broke off. This was the first observation of tooth replacement in a European pachypleurosaur, the only other discovery of such an event was made in China.

Classification

Pachypleurosaurs were originally and are often still included within the Nothosauroidea (Carroll 1988, Benton 2004). In some more recent cladistic classifications, however, (Rieppel 2000), they are considered the sister group to the Eosauropterygia, the clade that includes the nothosaurs and plesiosaurs. In the 2023 description of Luopingosaurus, Xu et al. found support for a similar hypothesis, recovering Pachypleurosauroidea as the sister taxon to the Eusauropterygia, a clade which contains both Nothosauroidea and Pistosauroidea. The results of their phylogenetic analyses are shown in the cladogram below:

Sauropterygia

Placodontia



Hanosaurus


Eosauropterygia
Pachypleurosauroidea


Majiashanosaurus




Diandongosaurus



Dianmeisaurus







Dawazisaurus




Panzhousaurus



Keichousauridae

Dianopachysaurus



Keichousaurus



Pachypleurosauridae


Dactylosaurus




Anarosaurus



Odoiporosaurus







Serpianosaurus



Neusticosaurus





Prosantosaurus




Qianxisaurus




Wumengosaurus




Luopingosaurus



Honghesaurus













Eusauropterygia

Nothosauroidea



Pistosauroidea





See also

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