plesiosaur us

[Pref. plesio-, and Greek sauros =a lizard.] Palæont .: The typical group of the order Plesio sauria (q. v.). The skin was naked, the head com paratively small, neck disproportionately long, and the tail short. Teeth conical and pointed, with longitudinal striations, each sunk in an independent socket. The paddles consist only of the five digits, without marginal o icles. It was certainly Plesiosaur us Dolichodeirus. a. Humerus; b. Ulna; c. Radius. aquatic; most probably marine, though it may have occasionally the shore. Its organization would fit it for swimming on or near the surface, and the length and flexibility of its neck would be eminently serviceable in capturing its prey. Plesiosaur us is only known with certainty to have existed from the time of the Lower Lias to the Chalk: and it is especially characteristic of the Lias.