Researchers believe "Predator X" could have fed on other big reptiles
A giant fossil sea monster found in the Arctic had a bite that would have been able to crush a 4x4 car, according to its discoverers.
Researchers say the marine reptile, which measured an impressive 15m (50ft) long, had a bite force of about 16 tonnes (35,000lbs).
The creature's partial skull was dug up last summer in the Arctic archipelago of Svalbard by a Norwegian-led team.
Dubbed "Predator X", it patrolled the oceans some 147 million years ago.
Its jaws may have been more powerful than those of a Tyrannosaurus rex, though estimates of the dinosaur's bite vary substantially.
It is thought to belong to a new species of pliosaur - a group of large, short-necked reptiles that lived at the time of the dinosaurs.
But even by the standards of this group, the creature's size has astonished scientists.
Its estimated length exceeds that of another large pliosaur, dubbed "The Monster", which was uncovered in Svalbard a year earlier than this one.
Expedition leader Jorn Harald Hurum, from the University of Oslo's Natural History Museum, said "The Monster" would have been big enough to chomp on a small car.
He said the bite estimates for the latest fossil forced a re-think.
This one, he said, might have been able to "crush a Hummer", referring to General Motors' large 4x4 vehicle.
Researchers say the shape and proportional size of the brain resembles that of another "apex predator": the great white shark.
The biggest marine reptile on record is a 21m-long ichthyosaur, Shonisaurus sikanniensis, from Triassic Period rocks in British Columbia, Canada.