Mosasaurus Partial Jaw, from Morocco (REF:MPJ1)

Mosasaurs are a group of large marine reptiles and like flying reptiles are not dinosaurs but lived during the reign of the dinosaurs, in the Cretaceous Period 100-65 Million Years Ago.

The first Mosasaurs fossil remains were discovered in a limestone quarry at Maastricht on the Meuse, Netherlands in 1764, (Latin Mosa meaning the ‘Meuse river', and Greek sauros meaning 'lizard')

Mosasaurs lived in the seas during the Cretaceous. Fossils have been found on almost every continent from North and South America, to Europe, Asia, and Australia.

There was a number of species of Mosasaurs ranging from the smaller Dallasaurus (3 feet in length) to the large Tylosaurus (which could up to 50 feet in length)

They moved by propelling themselves by mainly moving the large fin on their tail in a side to side motion they could be fast, sleek and powerful. It had been thought they swam like a sea snakes undulating their entire bodies from side to side. However, new evidence suggests that many advanced mosasaurs had large, crescent-shaped flukes on the ends of their tails, similar to those of sharks.

Stomach contents of mosasaurs reveal ammonites, bony fish, sea turtles, plesiosaurs, and even sea birds!

It appears they could eat whatever they wanted and although mosasaurs were aquatic, they were reptiles, which means they had to surface to breathe air, like a sea turtle today.