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Unfortunate dinosaur in New Jersey suffered from horrific case of arthritis

hadrosaurus
A painting showing a variety of dinosaurs including the duck-billed hadrosaur.
(Jason Poole)

Dinosaurs had joint pain too.

In a study published Tuesday in Royal Society Open Science, researchers describe the first known dinosaur to suffer from a crippling form of arthritis. The condition, known as septic arthritis, also occurs in humans, birds and crocodiles. 

The afflicted dinosaur was discovered in what is now southern New Jersey. Researchers only recovered its two forearm bones — the radius and ulna — so they can’t tell exactly what species it was. However, they said it was probably a duck-billed dinosaur, known as a hadrosaur, and that it lived about 70 million years ago.  

Both of the dinosaur bones were covered with a strange bony growth the texture of cauliflower. Further investigation revealed that the elbow joint had completely eroded away and then fused. 

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“It probably had a partially bent arm with either little or no movement at the elbow. Kind of like Igor from ‘Frankenstein,’” said study first author Jennifer Anné, who recently completed her PhD from the University of Manchester in Britain.  “It also probably would have had a limp.”

A 3-D scan shows a bony, cauliflower-like growth on the dinosaur’s radius bone.
A 3-D scan shows a bony, cauliflower-like growth on the dinosaur's radius bone.
(Jennifer Anné et al )

The researchers said it is hard to tell how much agony the situation caused the unfortunate dinosaur.

“Reptiles and birds both deal with horrific injuries, so although I’m sure it hurt, it probably trudged through,” Anné said. 

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She first heard about the unusual dinosaur bones a little over a decade ago.

“We have been scheming to scan it for almost 10 years,” she said. “We just needed the right equipment.”

Like many fossils discovered in this part of New Jersey, these two specimens are extremely fragile. That’s because the area was under the ocean 70 million years ago. Dinosaur fossils that have been found there are prone to a condition called pyrite disease that can cause them to turn to dust when they are touched. 

Since the researchers couldn’t slice the fossil to peer inside it, Anné and her collaborators used the microCT scanning facilities at the Center for Nanoscale Systems at Harvard University. Medical CT scanners are powerful enough to see through bone, but the investigators needed one that could see through rock. 

After comparing the dinosaur’s symptoms to those seen in other animals, the researchers ultimately concluded that their specimen suffered from septic arthritis, which is caused by an infection in a joint.

In modern-day reptiles, the condition is usually contained to the area where the infection began, but when mammals get it, it often spreads to multiple areas of the skeleton, Anné said.

“Unfortunately, we don’t have the rest of the hadrosaur to see how far it might have spread, though I’m betting it would have at least affected the humerus [upper arm bone] at the elbow joint as well,” she said.

Poor ancient dinosaur.

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deborah.netburn@latimes.com

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