Suborder of aquatic reptiles which enter the fossil record in the late Triassic, and which are common in many Jurassic and Cretaceous sediments. In appearance they were likened by Buckland to ‘a snake strung through the body of a turtle’, and some grew up to 15 m in length. There were also short-necked types, as well as the swan-necked. The former are defined as the superfamily Plesiosauroidea (e.g. Plesiosaurus and Muraenosaurus), the latter as the superfamily Pliosauroidea (e.g. Pliosaurus and Trinacromerum), the two superfamilies making up the suborder.
Subjects: Earth Sciences and Geography.