Temporal range: Jurassic, 199–145 Ma
Predator X is an informal name for a prehistoric marine predator, thought by scientists to be a new species in the pliosaur family. A partial skull, a complete flipper and some assorted remains, including a section of vertebra of two individuals was excavated in mid-2008 in Svalbard, near the Arctic, by a Norwegian team led by Dr. Jørn Hurum. It is claimed by researchers to be the "most fearsome animal ever to swim in the oceans."
The remains were discovered in June 2006 during a two-week expedition led by Dr. Hurum of the Natural History Museum at the University of Oslo. The team found 20,000 fragments of the creature's skeleton, which is being preserved and assembled at the museum. Due to the distribution pattern of pliosaurs, scientist believe that species were cosmopolitan, like some groups of modern-day whales.
The remains are very close to that of Liopleurodon, an animal well known from several fairly complete skeletons. Using Liopleurodon as a guide, the Svalbard is estimated to have been 15 metres (49 ft) long, 45,000 kilograms (99,000 lb) in weight and had teeth 30 centimetres (12 in) long.
The jaws of the creature may have been able to exert more force than those of a Tyrannosaurus rex, with one news source stating the bite was over 10 times more powerful than any modern animal and four times more powerful than that of a Tyrannosaurus. It is estimated to have been alive approximately 147 million years ago.
Analysis of bones from the four flippers suggest that the animal cruised using just two fore-flippers, using the back pair for extra speed when pursuing and capturing prey.
A television programme entitled Predator X first aired on History in 2009. It was also featured in the fourth episode of the BBC documentary series Planet Dinosaur in 2011, where it is shown hunting Kimmerosaurus, a smallerplesiosaur. The scene is based on damages to the one known skull of Kimmerosaurus, showing damage consistent with an attack of a very large animal with Liopleurodon-like dentition.