Kronosaurus is a genus of marine reptile belonging to the group Pliosauridae. It lived during the Early Cretaceous period, approximately 125 to 100 million years ago. The first fossils of Kronosaurus were discovered in Australia in the mid-19th century, and since then, additional findings from various parts of the world have helped reconstruct its formidable anatomy.

Kronosaurus was a giant pliosaur from Australia and South America. It had four wing-like flippers and many pointed teeth. They probably utilized the flippers the same way marine turtles do - they sort of “fly” under water.

It´s diet consisted of all kinds of marine animal, from small fish and squid to other plesiosaurs. Some long neck plesiosaur skeletons bear pliosaur tooth marks, which confirms that the pliosaurs preyed on the plesiosaurs.

It is most famous from a reconstructed skeleton that is desplayed at the Harvard Museum of Comparative Zoology at Massachusetts, USA. The reconstruction is 13 metres or 43 feet long, which is inaccurate. According to newer research is skull crest is too large and the body should be shorter. Kronosaurus is estimated to be only 30 feet or 9 metres long. Pliosaurs like Kronosaurus lived through the Jurassic period up until the early Cretaceous.