The fossils of a 170-million-year-old ancient marine reptile from the Age of Dinosaurs have been identified as the oldest-known mega-predatory pliosaur – a group of ocean-dwelling reptiles closely related to the famous long-necked plesiosaurs.
(I suspect that the associated photo is not a picture of the pliosaur.)
https://www.alphagalileo.org/en-gb/Item-Display/ItemId/238555