Leviathan’s big brother

Last year Norwegian scientists unearthed a fossilised Pliosaur on the arctic island of Spitsbergen. It was not until earlier this week that the bones of the 150 million year old specimen were fully assembled. It turns out that it is the largest marine reptile known to science, a full 20% larger than the previous biggest marine reptile - a pliosaur from Australia called Kronosaurus.

Nicknamed "The Monster", the immense creature would have measured 15m (50ft) from nose to tail. Dr Jorn Hurum, from the University of Oslo Natural History Museum, said "We have carried out a search of the literature, so we now know that we have the biggest pliosaur. It's not just arm-waving anymore. The flipper is 3m long with very few parts missing. On Monday, we assembled all the bones in our basement and we amazed ourselves - we had never seen it together before."

Pliosaurs were a short-necked form of plesiosaur, a group of extinct reptiles that lived in the world's oceans during the age of the dinosaurs. A pliosaur's body was tear drop-shaped with two sets of powerful flippers which it used to propel itself through the water. "These animals were awesomely powerful predators," said palaeontologist Richard Forrest. "If you compare the skull of a large pliosaur to a crocodile, it is very clear it is much better built for biting... by comparison with a crocodile, you have something like three or four times the cross-sectional space for muscles. So you have much bigger, more powerful muscles and huge, robust jaws. A large pliosaur was big enough to pick up a small car in its jaws and bite it in half."

"There are a few isolated bones of huge pliosaurs already known but this is the first find of a significant portion of a whole skeleton of such a giant," said Angela Milner, associate keeper of palaeontology at London's Natural History Museum "It will undoubtedly add much to our knowledge of these top marine predators. Pliosaurs were reptiles and they were almost certainly not warm-blooded so this discovery is also a good demonstration of plate tectonics and ancient climates"One hundred and fifty million years ago, Svalbard was not so near the North Pole, there was no ice cap and the climate was much warmer than it is today."

The Monster was excavated in August 2007 and taken to the Natural History Museum in Oslo. Team members had to remove hundreds of tonnes of rock by hand in high winds, fog, rain, freezing temperatures and with the constant threat of attack by polar bears. They recovered the animal's snout, some teeth, much of the neck and back, the shoulder girdle and a nearly complete flipper. Unfortunately, there was a small river running through where the head lay, so much of the skull had been washed away. A preliminary analysis of the bones suggests this beast belongs to a previously unknown species.