The giant mosasaur occupied the same ecological niche as today's killer whales and great white sharks.

Once upon a time, 72 million years ago, the Pacific seas were terrorised by a giant monster ... The apex predator was a mosasaur, an extinct, large marine reptile from the Late Cretaceous period.

Other fossils found at the same site suggest the egg could have belonged to a giant marine reptile called a mosasaur, although it is unclear whether the egg was laid on land or at sea. The study ...