a large fossil marine reptile of the Mesozoic era, with a broad flat body, large paddle-like limbs, and typically a long flexible neck and small head 蛇颈龙
Infraorder Plesiosauria, superorder Sauropterygia: several families, including Plesiosauridae 蛇颈龙下目,鳍龙总目:数科,包括蛇颈龙科
语源
mid 19th cent.: from modern Latin Plesiosaurus, from Greek plēsios 'near' + sauros 'lizard'