OSLO, Dec 4: Norwegian researchers have discovered a second rare fossil in the Arctic of a pliosaur, a giant reptile described by experts as the “T-Rex of the oceans”, the project leader said on Tuesday.

“We think it is a species unknown until now. Our pliosaur shows significant differences from those discovered in France and Britain,” Joern Hurum of Oslo University’s paleontology department said.

The fossil, including parts of the skull, was discovered during a dig this past summer in the Svalbard archipelago, about 1,000km from the North Pole.

The bones were found near those of a first pliosaur fossil found a year earlier.

Paleontologists had hoped to find the first animal’s entire skeleton — it is believed to have been 10 meters (33 feet) long and weigh between 10 and 15 tonnes — but uncovered only large fragments, including its ribcage, a shoulder and leg.

Pliosaurs lived about 150 million years ago, when the Svalbard region was under water, and swam the seas at the same time as dinosaurs dominated the land.

They resembled giant sea lions, with four fins and a snout similar to those of a crocodile, and were the ocean’s equivalent of the land-based Tyrannosaurus Rex, according to experts.—AFP