- ichthyosaur - any of several marine reptiles of the Mesozoic having a body like a porpoise with dorsal and tail fins and paddle-shaped limbs
--1 is a kind of archosaur, archosaurian, archosaurian reptile
--1 is a member of Ichthyosauria, order Ichthyosauria
--1 has particulars: ichthyosaurus; stenopterygius, Stenopterygius quadrisicissus