ichthyosaurus

[ik-thee-uh-sawr-uh s] /ˌɪk θi əˈsɔr əs/
noun, plural ichthyosauruses.
Origin
1825-35; < Neo-Latin; see ichthyo-, -saurus
British Dictionary definitions for ichthyosaurus

ichthyosaur

/ˈɪkθɪəˌsɔː/
noun (pl) -saurs, -sauruses, -sauri (-ˈsɔːraɪ)
1.
any extinct marine Mesozoic reptile of the order Ichthyosauria, which had a porpoise-like body with dorsal and tail fins and paddle-like limbs See also plesiosaur