Liopleurodon

Liopleurodon was a huge animal that can bite an Opthalmosaurus in half.

Series 4
In Series 4 of Primeval there is going to be a Huge Pliosaur. That Pliosaur might be a Liopleurodon, because it is huge, and it is a pliosaur. But it could be a lot of other animals as well. Kronosaurus is one of them.