August 11 , 2016

by Jen Viegas

A long-gone duck-billed dinosaur has just been diagnosed with a horrific medical condition: septic arthritis.

The discovery, a first for dinosaurs, reveals that even prehistoric animals suffered from septic arthritis, a painful joint infection still seen in some modern birds, crocodiles and people. The findings are published in the journal Royal Society Open Science.

Lead author Jennifer Anné of the University of Manchester told Discovery News that "arthritis has been noted in a wide range of dinosaurs, and other animals, both modern and fossil. Septic arthritis represents further complications caused by arthritis in the form of infection."

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She and colleagues Brandon Hedrick and Jason Schein used the microCT scanning facilities at the Center for Nanoscale Systems at Harvard University to analyze the remains of a hadrosaur unearthed at the Navesink Formation in New Jersey. The dinosaur lived about 70 million years ago.

Photo: Hadrosaurus mount at the Academy of Natural Sciences, Drexel University. Credit: Wikimedia Commons

Hadrosaurs were plant eaters with duck-like bills and strong jaws evolved for grinding plants with their multiple rows of teeth. Many such dinosaurs sported massive crests on their heads, believed to be used for displays before mating.

The scientists found that their hadrosaur had septic arthritis in its elbow that caused a fused joint covered in bony growths. Germs, as from a bacterial or fungal infection, can appear in this infection if they travel through the bloodstream and reach one or more joints. A penetrating injury can also deliver germs directly to a joint.

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Anné said that "having a destroyed or possibly fused elbow would have (made) that arm fairly useless. I imagine he/she had a bit of limp going on, or perhaps didn't even put weight on that arm."

She continued that septic arthritis is similar to osteomyelitis, an infection of the bone and bone marrow that can cause inflammation and destruction of the bone. Osteomyelitis previously was detected in dinosaurs.

Unlike that condition, septic arthritis is due to an infection that starts outside of the bone. The researchers were able to rule out osteomyelitis due to the observed condition's location around the dinosaur's elbow joint and because of the nature of the associated bone growth.

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The poor hadrosaur most likely lived in a great deal of pain, possibly following an injury caused by a meat-eating dinosaur or other predator. Nevertheless, the fact that the hadrosaur carried on in spite of the health challenge shows that the dinosaur at least possessed a certain amount of fortitude.

As Anné said, even to this day, "both birds and reptiles can deal with some pretty horrific pathologies, especially crocodiles."