Mosasaur
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
List of creatures in Primeval
The skull was more robustly built than other Mosasaurs, as the mandibles articulated very tightly with the skull. It had a deep, barrel-shaped body, and with its fairly large eyes, poor binocular vision, and poorly developed olfactory bulbs, experts believe that "Mosasaurs" lived near the ocean surface, where it preyed on fish, turtles, ammonites as well as smaller "Mosasaurs". Because of its robust skull and tightly articulating jaws, mosasaurs was unable to swallow prey-items whole in the manner of earlier mosasaurs, such as "Tylosaurus". Instead, with the aid of its curved, knife-like teeth, mosasaurs was able to tear its prey into more manageable pieces that could be more easily swallowed.