Pachypleurosauria is an extinct clade of primitive reptiles from the Triassic period. Pachypleurosaurs vaguely resembled aquatic lizards, with elongate forms ranging in size from , 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.
Classification
Pachypleurosaurs were traditionally 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 also includes the
and
.
[ In the 2023 description of Luopingosaurus, Xu et al. supported a similar hypothesis, recovering Pachypleurosauroidea as the sister taxon to the Eusauropterygia. The results of their phylogenetic analyses are shown in the cladogram below:]
Sources
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Benton, M. J. (2004), Vertebrate Paleontology, 3rd ed. Blackwell Science Ltd
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Carroll, R.L. (1988), Vertebrate Paleontology and Evolution, WH Freeman & Co.
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Oliver Rieppel, (2000), Sauropterygia I, placodontia, pachypleurosauria, nothosauroidea, pistosauroidea: In: Handbuch der Palaoherpetologie, part 12A, 134pp. Verlag Dr. Friedrich Pfeil Table of contents
External links
