An artistic impression of a fish-like reptile catching a smaller plesiosaur.
Last Update: Friday, October 6, 2006. 6:01am (AEST)

'Monster' fossil unearthed in Arctic

Scientists have found a fossil of a "monster" fish-like reptile in a 150 million-year-old Jurassic graveyard on an Arctic island off Norway.

The Norwegian researchers have discovered remains of a total of 28 plesiosaurs and ichthyosaurs - top marine predators when dinosaurs dominated on land - at a site on the island of Spitsbergen, about 1,300 kilometres from the North Pole.

University of Oslo Assistant Professor Joern Hurum says the animals were huge.

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

"We believe the skeleton is intact and that it's about 10 metres long."

The skeleton is from a type of plesiosaur with a short neck and massive skull, which the team have dubbed "the monster".

Assistant Professor Hurum says such pliosaurs are known from remains in countries including Britain and Argentina but no complete skeleton has been found.

The skull of the pliosaur, perhaps a distant relative to Scotland's mythical Loch Ness monster, is among the biggest on record.

Scientists will return next year to try to excavate the entire fossil, buried on a hillside.

Plesiosaurs, which swam with two sets of flippers, often preyed on smaller dolphin-like ichthyosaurs.

All went extinct when the dinosaurs vanished 65 million years ago.

The scientists rate the fossil graveyard "one of the most important new sites for marine reptiles to have been discovered in the last several decades".

"It is rare to find so many fossils in the same place - carcasses are food for other animals and usually get torn apart," Assistant Professor Hurum said.

Assistant Professor Hurum says the reptiles had not all died at the same time in some Jurassic-era cataclysm but had died over thousands of years in the same area, then become preserved in what was apparently a deep layer of black mud on the seabed.

At that time, the area of Spitsbergen was under water several hundred kilometres further south, around the latitude of Anchorage or Oslo.

Assistant Professor Hurum says the presence of fossils was also an interesting pointer for geologists hunting for oil and gas deposits in the Barents Sea to the east.

"A skull we found even smells of petrol," he said.

- Reuters