1. Extinct marine reptile of the Mesozoic era, characterized by a small head on a long neck, short tail, and four paddle-shaped limbs
   "Plesiosaurs are often associated with the 'Loch Ness Monster' legend";
   - plesiosaurus

Derived forms: plesiosaurs

Type of: archosaur, archosaurian, archosaurian reptile

Part of: genus Plesiosaurus

Encyclopedia: Plesiosaur