Ancient Arthritis in Marine Reptile Jaws

The gigantic jaws of the Wiltshire Pliosaurus

Today, billions of dollars a year are spent on anti-inflammatory drugs and paracetamols to combat arthritis. It is an inflammation of the joints, a condition that can strike anywhere in the body, but is particularly common in the hands. Yet some unlucky people can experience it in their jaws. Eating and talking is painful to say the least. Now imagine that the jaws are over two metres in length.

A new study has shown that pliosaurs, giant marine predators which lived during the Cretaceous, suffered a degenerative bone condition similar to human arthritis. A few years ago, palaeontologists recovered a complete lower jaw from a Pliosaurus from Jurassic strata near Westbury in Wiltshire. It was kept in the collections at Bristol City Museum and Art Gallery until an MSc student, Dr Judyth Sassoon used it for her research project. She noticed that the bone was eroded on the left side, resulting in a crooked jaw. Analysis of the section revealed a porous structure similar to the inflammation connected with arthritis.

Luckily for the owner, its jaw muscles were immensely powerful and coupled with 20 centimetre long serrated teeth, it was still a formidable carnivore. The size of the beast and the fused cranial bones suggests that the creature was old when it died, meaning that it was still able to hunt despite its crooked mandibles. 'In the same way that aging humans develop arthritic hips, this old lady (based on the morphology of the skull) developed an arthritic jaw, and survived with her disability for some time.' Further analysis revealed an unhealed fracture which probably led to her death. As a broken jaw would mean she was unable to feed or fend for herself.