Also known as: plesiosauria, plesiosaurus
Plesiosauria or plesiosaurs are an order or clade of extinct Mesozoic marine Reptiles, belonging to the Sauropterygia. Generally depicted having an ovoid body, four Flippers, long neck, and a comparatively small head. It's notable that not all real-life plesiosaurs have long necks, so this tag applies to any creature with the basic body plan of a plesiosaur.
List of plesiosaurs
External Links
https://en.wikipedia.org/wiki/Plesiosaur