The Pliosaurs were Mesozoic marine reptiles that arose in the Late Triassic or Early Jurassic and persisted till the Late Cretaceous. They were related to modern lizards and snakes, but were fully aquatic, the largest species reaching 15 m in length. All species seem to have been strict carnivores, and at least one species gave birth to live young.
A forthcoming paper in the journal Acta Palaeontologica Polonica by Peggy Vincent of the Département Histoire de la Terre at the Muséum National d’Histoire Naturelle and the Staatliches Museum für Naturkunde, Nathalie Bardet, also of the Département Histoire de la Terre at the Muséum National d’Histoire Naturelle and Emanuela Mattioli of the Laboratoire de Géologie de Lyon at Université Lyon describes the discovery of a new Pliosaur from the Early Jurassic of Normandy.
The new Pliosaur has been identified from a partial skull and several vertebrae from the Pliensbachian (an Early Jurassic stage; roughly 183.0-189.6 million years ago) Roche-Blain Quarry, at Fresney-le-Puceux, near Laize-la-Ville, south of Caen. The skull is elongated and narrow, at about 470 mm. It does not closely resemble any previously known Pliosaur, and has been named as Cryonectes neustriacus, Cryonectes meaning cold swimmer (the Pliensbachian is thought to have been quite cool) and neustriacus meaning from Neustrie, a Frankish kingdom that covered much of northern France.
Ventral view of the skull of Cryonectes neustriacus. From Vincent et al. (2012).
See also A Pachycormiform Fish from the Lower Jurassic Posidonia Shale, A Pregnant Plesiosaur, The Weymouth Pliosaur and Reptiles on Sciency Thoughts YouTube.