Skull Of Jurassic Sea Creature Shows That Even Dinosaurs Had Arthritis
May 16, 2012

Skull Of Jurassic Sea Creature Shows That Even Dinosaurs Had Arthritis

Arthritis, an often debilitating joint disorder that affects millions and millions of people around the world, may have also caused pain and discomfort for dinosaurs and other ancient reptiles more than 150 million years ago, according to new research from the University of Bristol.

Researchers, led by Bristol´s Dr. Judyth Sassoon, were fascinated to find a degenerative condition similar to arthritis in the jaw of a female pliosaur -- an ancient sea creature that lived during the Late Jurassic Period.

This is the first time an arthritis-like disease has been found in fossilized Jurassic reptiles. Usually capable of easily tearing the flesh from its prey with its giant eight-inch teeth, the inflamed jaw eventually kept the animal from feeding, which ultimately led to her death.

The specimen, discovered in Westbury, Wiltshire, had been kept in the collections of the Bristol City Museum and Art Gallery, where Sassoon first saw it. The 26-foot-long pliosaur was a terrifying beast with a large, crocodile-like head, short neck, whale-like body, and four powerful flippers used for propelling it through the waters in search of prey.

The researchers, publishing their results in the journal Paleontology, said the degenerative condition had eroded the left jaw joint of the animal, displacing the lower jaw to one side. It appears the creature lived with the crooked jaw for many years, because there are marks on the bone of the lower jaw where the teeth from the upper jaw impacted on the bone during feeding.

“In the same way that aging humans develop arthritic hips, this old lady developed an arthritic jaw, and survived with her disability for some time,” said Sassoon. “But an unhealed fracture on the jaw indicates that at some time the jaw weakened and eventually broke.”

“With a broken jaw, the pliosaur would not have been able to feed and that final accident probably led to her demise,” added Sassoon.

“You can see these kinds of deformities in living animals, such as crocodiles or sperm whales and these animals can survive for years as long as they are still able to feed,” Professor Mike Benton, a study collaborator, told The Telegraph. “But it must be painful. Remember that the fictional whale, Moby Dick from Herman Melville's novel, was supposed to have had a crooked jaw!”

Sassoon and colleagues found signs that the skeleton was that of an old female who had developed the condition with age. Its large size, and the fused skull bones, suggests maturity. Also indications of its gender, is the skull crest, which sits low -- experts presume males had higher crests.

The Pliosaur specimen is an amazing example of how the study of disease found in fossils can help researchers reconstruct an animal´s life history and behavior and shows that even a prehistoric apex predator such as the pliosaur can succumb to the diseases of old age.