Ancient seas were dominated by huge monstrous reptiles, like plesiosaurs, marine reptile with flipper like members, similar to those found in modern marine turtles, but with very long necks, quite similar to the monster from the stories about the seasnake. They disappeared because of the same event that led to the extinction of the dinosaurs.

New remains of a bus-sized prehistoric huge plesiosaur found on the remote Arctic Svalbard islands, about 1,300 km (810 mi) from the North Pole and 500 km (300 mi) north of Norway's mainland, could represent a new species for science.

"Initial excavation of a site on the Svalbard islands in August yielded the remains, teeth, skull fragments and vertebrae of a reptile estimated to measure nearly 40 feet long," said lead researcher Joern Harald Hurum, an assistant professor at the University of Oslo.

This plesiosaur could belong to the same species as another individual, whose remains were discovered nearby on Svalbard in 2006.

The fossils were dated 150 million years old (during the Jurassic era), and belonged to a giant pliosaur, a kind of plesiosaur with short neck and massive skull, more adapted to deep diving than the classical plesiosaurs, looking like a crocodile with turtle flippers. These voracious reptiles were a kind of Tyrannosaurus rex of the oceans.

"One of them was this gigantic monster, with vertebrae the size of dinner plates and teeth the size of cucumbers," said Hurum.

"We are regularly seeing new species of plesiosaurs popping up - in a way because, in the past 10 or 15 years, there has been what we call a renaissance in plesiosaur research," Mark Evans, a plesiosaur expert at the Leicester City Museums in Britain, told Reuters.

"The team had only managed to excavate a 3-meter (yard) area of the find," said Hurum, whose team will continue the dig in 2008.