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The giant jaws of a huge marine reptile are now on permanent display at the Dorset County Museum following its formal unveiling by Sir David Attenborough

Dating back around 155 million years, the pliosaur skull was discovered on the nearby Jurassic Coast World Heritage Site, and is one of the largest and best preserved fossils of its kind ever found.

Belonging to a creature up to 18m in length, the skull is a staggering 2.4 m long and is believed to have possessed the biggest bite of all time – powerful enough to break a small car in half.

The likely size of the Dorset pliosaur compared with a human and a killer whale.

The World's Biggest Bite!

The fossil bones of this pliosaur skull were recovered by amateur fossil collector Kevan Sheehan between 2003 and 2008, as they were washed out of a landslide on the coast in Weymouth Bay. The largest piece weighed over 80 kg. Kevan missed only four pieces, three of which were recovered by two other collectors.

In 2003, Kevan found three massive sections of the jaw lying at the base of the cliff, freshly washed out by the sea. Over the next five years he returned to the site after rough weather and rain, patiently recovering the pieces as they became exposed. This is an incredible achievement for an individual collector, and a sign of his dedication to the recovery of something that would otherwise have been lost to the sea. The three smaller pieces were found by other local collectors, Patrick Clarke and Shirley Swaine. One small piece at the back of one jaw is lost, while the front of the jaw was probably uncovered many years ago. It could have been washed away or it could be lying in a collection somewhere not yet linked to this find.

Sir David Attenborough with the Pliosaur Skull

Jurassic Coast Trust © 2011

Pliosaur at the Dorset County Museum

The find was originally publicised in October 2009. Since then hundreds of hours have been spent carrying out a detailed analysis and cleaning away the rock to expose the detail of the fossil underneath.

Richard Edmonds, Earth Science Manager for the Jurassic Coast Team said:

“It is an amazing achievement to have recovered this fossil from an eroding cliff over such a long period of time and without losing any important pieces. Fossil collectors have always played an essential role in the recovery of specimens important to science, and the emergence of this specimen clearly demonstrates that the approach of responsible collecting adopted on the Jurassic Coast World Heritage Site is proving effective.”

Along side this conservation work an intensive programme involved the Jurassic Coast team and Dorset County Museum working together to produce an exciting, interactive display showcasing the fossil with the theme ‘The World’s Biggest Bite’. Mounted dramatically on a specially constructed plinth that shows the jaws in an awe-inspiring open-mouthed position, the story of the fossil is interpreted through a series of film presentations accompanied by a life-size model of the pliosaur’s head.

Jon Murden, Director of Dorset County Museum, said:

“We are delighted to house such a world-class discovery at Dorset County Museum and the Weymouth Bay pliosaur is now a fitting centrepiece in our ever-popular Jurassic Coast gallery.”

Hilary Cox, Dorset County Council Cabinet member for community services, added:

“This project is a fantastic example of agencies working together to bring external funding into Dorset and deliver something really special. The pliosaur skull is a wonderful geological treasure, which can now be enjoyed not only by local people but also visitors to the county – boosting tourism trade into the bargain.”

Funding

The specimen was purchased by Dorset County Council's Museums Service, half its initial cost going to the collector and the other half to the landowner. Preparation (cleaning) and piecing the bones back together took 18 months of skilled, professional work. Funding has been provided by the Heritage Lottery Collecting Cultures programme, with match funding from Dorset and Devon County Councils. The restored specimen was formally unveiled here by Sir David Attenborough, on 8th July 2011.

Ongoing research

Scientific study is underway to discover how the animal lived and died, and how its bones became a living reef for encrusting animals. The specimen has already been scanned at the University of Southampton using its high-energy, micro-focus CT scanner - one of the most powerful of its kind in the UK. The results have been used to reconstruct a three dimensional digital model of the entire skull, revealing fine details of the creature's internal structure that would otherwise remain a mystery. The University of Bristol are using this CT scan data to understand just how powerful the bite may have been. Experts from the University of Portsmouth will study the fossilisation process, while mud associated with the bones has been sent to the University of Plymouth, to see if any fossil plankton were preserved. Sediment removed from the bones will be studied by experts in the Natural History Museum in search of bones and teeth of animals that may have hunted around the dead skeleton.

New Species

The Pliosaur Skull has recently been declared as a species new to science and named in honour of its finder Kevan Sheehan. The new name, Pliosaurus kevani, is published in the on-line journal PLOS ONE.

Mr Sheehan said; ‘This is a great day for Kevans around the world!’

Pliosaurus was a giant oceanic predator with a skull 2 metres long and body perhaps 12 metres in length. It was in fact the most powerful, scariest marine monster of all time, capable of biting the biggest great white shark alive today, clean in half (although they never existed at the same time). Despite their giant size, the oldest Pliosaurus species had many teeth, suggesting a diet of fish but over time they developed fewer, stronger teeth suggesting they evolved to hunt large prey such as big fish and other marine reptiles; plesiosaurs and ichthyosaurs. Indeed, there are spectacular examples of bones, particularly limbs with massive bite marks; just like many of today’s predators, pliosaurs probably disabled their prey and allowed them to weaken through blood loss before going in for the kill.


The Dorset specimen, known as the and ‘the World’s Biggest Bite’, is one of the most complete and best preserved skulls ever found and as a result it has provided new insights into our understanding of how these enormous animals evolved. Giant pliosaurs were first found in the UK in the early 1800s, but most fossils were fragmentary, so their species diversity has been uncertain. The scientific paper has taken a new look at both the Dorset specimen and two other skulls discovered near Westbury over the last 30 years (the Westbury pliosaurs are on display at Bristol City Museum and Art Gallery). That study has led to a revision of the group and the naming of both those specimens as new species as well; Pliosaurus carpenteri after the collector, Simon Carpenter and Pliosaurus westburyensis.

One of the most significant conclusions from the paper is that the genus Pliosaurus appears to have developed a highly effective body plan that remained little changed for millions of years in the Late Jurassic sea. During that time just a handful of species evolved and this is unlike most top predators in the fossil record which reach dominance but were then typically swiftly replaced by different forms. The research has been undertaken by a team of vertebrate palaeontologists from Oxford, Bristol and Cambridge universities and with Leicester, Nottingham and the Sedgwick (Cambridge) museums together with independent researchers.

Mark Evans, Curator of Natural Sciences at Leicester Museum said:

“We have so few diagnostic specimens and the extraordinary thing is that whenever a specimen is diagnostic, it often turns out to be something new. We’ve effectively doubled the number of British Pliosaurus species in the paper.”

Pliosaurus dominated the seas around 150 million years ago in the Late Jurassic and similar forms appeared again in the Cretaceous. They have been found in northern Norway on the island of Svalbard (the famous Predator X of television fame), Canada, Mexico, Colombia and Australia. Despite the huge size of pliosaurs, identifiable specimens are rare in the fossil record; there is about 1 million years between the Weymouth Bay and Westbury specimens, more than 100,000 generations, yet they are only known from three described specimens. That is because most animals do not become fossilised while, as a top predator, there are far fewer individuals than their prey source. This is the nature of the science; trying to untangle the history of life from just a handful of specimens, but that also makes it exciting as new finds, providing new insights, will always come to light so long as collectors are out there rescuing the fossils when they become exposed.

For more information about the Jurassic Coast World Heritage Site, visit www.jurassiccoast.com

Other examples

The Weymouth Bay Pliosaur skull is exceptional because it is 95% complete, but it is not the biggest in the world. Fragments of larger specimens have been found in the brick pits of Oxfordshire. The skull of Kronosaurus, from Australia, was possibly up to 3 m long. Specimens of comparable size have been found in northern Norway, on the island of Svalbard, and in Colombia, South America.

Other pliosaur specimens are on display around the world at

  • Queensland Museum - an example Kronosaurus found in Queensland, Northeast Australia.

Plesiosaur and ichthyosaur specimens are on display in the UK at