Sauropterygia

Sauropterygia Temporal range: Lower Triassic – Upper Cretaceous
The pliosaur Kronosaurus hunts a plesiosaur: by Dmitry Bogdanov.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Superorder:	†Sauropterygia Richard Owen, 1860

The Sauropterygia was a superorder of successful aquatic reptiles that flourished during the Mesozoic era. They are united by an adaptation of their shoulder, designed to support powerful paddle strokes. Some later sauropterygians like the pliosaurs developed a similar mechanism in their pelvis.^[1]

1. ↑ Benton M.J. 2004. Vertebrate palaeontology. 3rd ed, Blackwell, Oxford.