Pachypleurosauria

Pachypleurosaurs Temporal range: Induan-Carnian,
Keichousaurus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Clade:	†Eosauropterygia
Suborder:	†Pachypleurosauria Nopcsa, 1928
Genera
†Diandongosaurus †Hanosaurus †Majiashanosaurus †Qianxisaurus †Wumengosaurus †Keichousauridae †Dianopachysaurus †Keichousaurus †Pachypleurosauridae †Anarosaurus †Dactylosaurus †Neusticosaurus †Odoiporosaurus †Pachypleurosaurus †Serpianosaurus †Prosantosaurus

Pachypleurosaurus

Pachypleurosaurs were primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from 20 cm to about a metre in length, 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, indicate that these animals fed on fish. In its subspecies Prosantosaurus, it could be 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 a teeth replacement on an european pachypleurosaurus, the only other discovery of such an event tooth was made in China.

Pachypleurosaurs were originally and are often still included within the Nothosauroidea (Carroll 1988, Benton 2004). In some cladistic classifications however (Rieppel 2000), they are considered the sister group to the Eusauropterygia, the clade that includes the nothosaurs and plesiosaurs.

Sources

• Benton, M. J. (2004), Vertebrate Paleontology, 3rd ed. Blackwell Science Ltd
• Carroll, R.L. (1988), Vertebrate Paleontology and Evolution, WH Freeman & Co.
• Rieppel, O., (2000), Sauropterygia I, placodontia, pachypleurosauria, nothosauroidea, pistosauroidea: In: Handbuch der Palaoherpetologie, part 12A, 134pp. Verlag Dr. Friedrich Pfeil Table of contents

External links

• Lepidosauromorpha: Pachypleurosauridae - Palaeos