— plesiosauroid , adj.
/plee"see euh sawr'/ , n.
any marine reptile of the extinct genus Plesiosaurus, from the Jurassic and Cretaceous periods, having a small head, a long neck, four paddlelike limbs, and a short tail.
[ Plesiosaurus (1821), equiv. to Gk plesí ( os ) near, close to + -o- -O- + saûros -SAUR; orig. so named because of its conjectured nearness to modern reptiles, relative to the ichthyosaurs ]