The first evidence of the signs of an avian-style respiratory infection has been discovered in a non-avian dinosaur. Discovered by a team of researchers from various institutions around the U.S., the 150-million-year-old dinosaur remains offer interesting new insights into how ancient animals lived and died.
The original study, “The first occurrence of an avian‑style respiratory infection in a non‑avian dinosaur,” was recently published in the Scientific Report.
The dinosaur in question was a juvenile sauropod (long-necked dinosaur) of the Diplodocidae family - the same that includes the iconic Diplodocus. Its age puts it squarely in the Jurassic period of the Mesozoic Era. Nicknamed "Dolly" when it was discovered in southwest Montana, its remains showed clear evidence of an aggressive infection near some of its neck vertebrae.
After being exhumed, the fossil remains were examined by scientists, including Cary Woodruff of the Great Plains Dinosaur Museum, who identified never before seen abnormal bony protrusions that had an unusual shape and texture. These protrusions were found to be in an area of each bone that would have been penetrated by air sacs in life.
Similar air sacs are found in modern birds too and are generally used for non-oxygen exchange with the respiratory system. In life, these air sacs would have connected to "Dolly's" lungs and formed an integral part of the dinosaur's respiratory system. CT imaging of the irregular protrusions revealed that they were made of abnormal bone that most likely formed in response to an infection.
“We’ve all experienced these same symptoms – coughing, trouble breathing, fever, and here’s a 150-million-year-old dinosaur that likely felt as miserable as we all do when we’re sick,” explained Woodruff.
This is interesting in and of itself, but it also reveals something potentially more groundbreaking. It is commonly believed that birds evolved from Ornithischia ("bird-hipped"), specifically therapod dinosaurs, not hulking sauropods like "Dolly". This could reveal that "bird-hipped" and"lizard-hipped" (technically called Saurischia) have more in common than once believed.
The findings of this study allowed its authors to speculate that respiratory infection could have been caused by a fungal infection similar to aspergillosis. This is a common respiratory illness that affects birds and reptiles today and can lead to bone infections, as seen in "Dolly".
"Dolly" is a gift from the deep past that keeps on giving
Not only that, but if the team is correct, this could help unlock the mysteries of the respiratory anatomy of these long-dead animals.
“This fossil infection in Dolly not only helps us trace the evolutionary history of respiratory-related diseases back in time, but it also gives us a better understanding of what kinds of diseases dinosaurs were susceptible to,” Woodruff explained.
It also makes "Dolly" feel more relatable and alive to us today so many millions of years later.
“This would have been a remarkable, visibly sick sauropod,” UNM Research Assistant Professor Ewan Wolff said. “We always think of dinosaurs as big and tough, but they got sick. They had respiratory illnesses like birds do today, in fact, maybe even the same devastating infections in some cases,” he added.
If their hypothesis is correct, and "Dolly" was suffering from an aspergillosis-like respiratory infection, the animal would have been in a great amount of discomfort. "She" would likely have experienced weight loss, coughing, fever, and breathing difficulties. This can be fatal in modern birds and would help explain the untimely death of this apparently juvenile specimen.
“We have to continue to expand our knowledge of ancient diseases. If we look hard enough, we may begin to understand more about the evolution of immunity and infectious disease,” Wolff explained. “When we work together between multiple specialties - veterinarians, anatomists, paleontologists, paleopathologists, and radiologists we can come away with a more complete picture of the ancient disease," he added.