Rare duck-billed dinosaur with arthritis

It seems arthritis has plagued joints since the prehistoric era, according to analysis of a deformed dinosaur bone, which suggests its owner suffered from septic arthritis.

The remains of a hadrosaur – a duck-billed dinosaur hailing from modern-day USA during the Late Cretaceous – were discovered in a quarry in New Jersey.

The find was significant for two reasons: first, because preserved specimens hailing from eastern North America are unusual to come by; and second, because the dinosaur’s elbow joint bore evidence of a serious medical condition.

The dinosaur’s forearm bones, the ulna and radius, were discovered, each around 50 to 70 centimetres in length. In a unique twist, the elbow joint was fused together by unusual growths along the bone.

To identify the reason behind this deformity, experts called upon the specialised knowledge of palaeopathologists – researchers into ancient disease and trauma.

As with other fossils found in this particular quarry, the specimen was in an especially fragile state. Due to pyrite disease – a chemical process that results in the decay of some fossils – the specimen is prone to crumbling, and cannot be handled excessively.

To get around this, researchers from the University of Manchester in the UK, New Jersey State Museum and the University of Massachusetts, Amherst used microCT technology to scan the bones and collect X-ray data on their insides.

This method also produces a virtual record of the remains, which will outlive the specimen in case of damage or deterioration.

According to the results, published this week in Royal Society Open Science, this internal analysis produced a diagnosis of septic arthritis, similar to arthritic conditions that occur in birds, reptiles and humans.

“The most likely explanation for the given pathology is a form of osteoarthritis, which is defined as any condition affecting movable joints by deterioration of articular cartilage,” the paper reads.

This is the first case of septic arthritis recorded in the dinosaur world, and researchers say the diagnosis offers a unique insight into the life histories of extinct animals.

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