Oldest Dinosaur Bone Infection Discovered in 220-Million-Year-Old Plateosaurus

The oldest known case of a bone infection has been discovered — not in a human, but in a dinosaur.

A recent study, published in the Swiss Journal of Paleontology, introduces us to a 220-million-year-old Plateosaurus that suffered from a bone infection in its right arm and shoulder. Although the dinosaur died from getting stuck in a mud pit, its chronic illness — identified as osteomyelitis — likely rendered its right arm completely useless and made its chances at escape more unlikely.

The discovery is both the oldest and largest known case of an infection present in dinosaur bones.

“Previous studies of osteomyelitis in dinosaurs report localized areas of infection, such as toe bones or a couple adjacent bones in the spine. Having an entire infected shoulder and upper arm is very unusual,” said Jordan Bestwick, postdoctoral fellow at the Department of Paleontology at the University of Zurich (UZH), in a press release. “Although we don’t know what initially caused the infection, the animal likely suffered from this disease for a substantial part of its life, possibly rendering its right arm useless.”

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Diagnosing Infection in Dinosaur Bones

In 2018, the almost-complete fossil of the nearly 26-foot-long Plateosaurus was found in what is now Switzerland’s Frick Valley. During the Late Triassic period when Plateosaurus’ roamed the Earth, the Frick Valley was a semi-arid basin prone to flooding that often caused large mud traps. Fossils of the Plateosaurus, a long-necked sauropod ancestor of the more famous Diplodocus, are commonly found in these former mud traps, as the bipedal dinosaur often found itself stuck.

A team from UZH used computer tomography (CT) scans to learn more about the dinosaur’s bones. They were able to do this using 3D micro CT scanners and a 2D fan-beam Linac scanner at the Swiss Federal Laboratories for Material Sciences that were big enough to accommodate the large arm and shoulder bones of the Plateosaurus.

The CT scans showed the presence of a severe case of osteomyelitis in the bone tissue. Osteomyelitis occurs when an external bacterial or fungal infection transmits to the bone via the bloodstream. This disease often causes extremely painful swelling of the bone marrow and can result in tissue death and permanent bone loss.

“Osteomyelitis affects many living animals, including mammals such as humans, as well as birds and reptiles. This disease is known to have affected several different dinosaur groups, including sauropods,” said Bestwick in the press release. “The affected bones in the shoulder and upper arm have unusually rough internal and external textures, altered shapes, and are even fused together — symptoms that are broadly typical of osteomyelitis.”

Dinosaur Osteomyelitis On Display

The Plateosaurus specimen is not only unique because of the presence and size of its bone infection. It is also now one of the only dinosaur displays in the world to feature a depiction of its chronic illness.

Both the fossilized remains and a life-size reconstruction of this Plateosaurus are on display at UZH’s Natural History Museum. The exhibit, located at the entrance to the museum, allows museum visitors to look at the evidence of the bone infection in the dinosaur’s arm and shoulder bones, while also seeing how its affected right arm would’ve looked in the flesh.

“Together with the paleo-reconstruction wizards from the Danish company 10 Tons, we created a reconstruction based on the skeleton that also showcases the disease on its right arm and shoulder. This makes the display one of the few worldwide where the reconstruction of an individual dinosaur includes its pathologies,” said Dennis Hansen, the lead creator of the exhibit from the Natural History Museum, in the press release.

Read More: How the Triassic Extinction Helped Dinosaurs Take Over the Planet

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• Swiss Journal of Paleontology. Osteology and histology of a Plateosaurus trossingensis (Dinosauria: Sauropodomorpha) from the Upper Triassic of Switzerland with an advanced chronic pathology

• Cleveland Clinic. Osteomyelitis (Bone Infection)

As the marketing coordinator at Discover Magazine, Stephanie Edwards interacts with readers across Discover’s social media channels and writes digital content. Offline, she is a contract lecturer in English & Cultural Studies at Lakehead University, teaching courses on everything from professional communication to Taylor Swift, and received her graduate degrees in the same department from McMaster University. You can find more of her science writing in Lab Manager and her short fiction in anthologies and literary magazine across the horror genre.

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