Cryptoclididae
Cryptoclididae is a family of medium-sized plesiosaurs that existed from the middle Jurassic to the early Cretaceous period. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans.Classification
In 2010, two supposed late Cretaceous members of the group were reclassified as other kinds of plesiosauroids. Kaiwhekea was reclassified to Leptocleididae, and Aristonectes was transferred to Elasmosauridae.
Cladogram based on Ketchum and Benson :