Eurhinosaurus

Eurhinosaurus ('well-nosed lizard') is an extinct genus of ichthyosaur from the Early Jurassic (Sinemurian - Toarcian) of Europe (England & Germany). It was a large genus, exceeding 6 m in length.

Paleobiology
Eurhinosaurus looked like a regular ichthyosaur, with a fish-like body including a dorsal and caudal fin, and large eyes, but had one distinct feature that set it apart from other ichthyosaurs. Its upper jaw was twice as long as the lower jaw and covered with sidewards-pointing 'teeth', like the sawfish's. It might have been used to search vegetation and crustaceans on the ocean bottom for prey (mainly by "swishing" it's upper jaw against the sea floor) like a sawfish, or to violently stab prey to death like swordfish, sailfish and marlins do. Interestingly, a Miocene cetacean, Eurhinodelphis, also developed a similar 'sword'.