Coughing, breathing difficulties and the long neck must have hurt terribly: Paleontologists have found signs of a respiratory disease in a fossil of a juvenile sauropod. The infection was apparently so severe that it spread to the bone tissue and caused growths. It was probably a form of so-called air sac inflammation, which is common in birds today. Bacterial or fungal pathogens are possible causes, say the researchers. The findings expand the previously limited knowledge about the diseases that once plagued dinosaurs.
From tumors to joint inflammation to infectious diseases such as Covid-19: numerous health problems make life difficult for humans and animals. It seems clear that the dinosaurs also suffered from various diseases. But what actually plagued the rulers of the Jurassic and Cretaceous periods can often only be guessed at, because fossil traces of diseases are rare. Knowledge is largely limited to diseases that cause pathologically altered bone structures.
For example, there are findings of bone cancer or inflammatory joint diseases in dinosaurs. One might think that the bony remains do not indicate the extent to which the animals were also affected by respiratory diseases. But as the study by the paleontologists around Cary Woodruff from the Great Plains Dinosaur Museum in Malta (USA) shows, this is apparently possible – in serious cases.
Strange bone growths in sight
Their findings are based on examining the fossil of an immature diplodocid—a large, long-necked herbivore of the sauropod family. The specimen, nicknamed “Dolly,” was discovered in southwest Montana and dates to the Late Jurassic period, around 150 million years ago. Examining the fossil, Woodruff and his colleagues found bony outgrowths on three cervical vertebrae that were unusual in shape and texture. They then devoted a more detailed analysis to this finding.
They report that the abnormal bone structures are each located in an area of the cervical vertebrae that was once penetrated by air sacs of the animal’s complex respiratory system. These structures were ultimately also connected to Dolly’s lungs, the scientists explain. The computer tomographic detailed analyzes of the anomalies showed that it was obviously not a type of growth caused by bone cancer. Because of the location, the researchers suspect they arose in response to a respiratory infection. This was so severe and chronic that it spread through the air sacs into the cervical vertebrae, causing the growths.
Based on the characteristics, the scientists suspect that the animal suffered from a so-called air sac inflammation with accompanying osteomyelitis. This is a respiratory disease that is widespread in modern birds and can be caused by various pathogens. Specifically, it could have been a form of aspergillosis – an infection with pathogenic fungi, the researchers say.
Sad fate 150 million years ago
Woodruff and his colleagues conclude that the fossil traces of the disease represent the first clear indication of a respiratory infection in a dinosaur. “This sheds light on the evolutionary history of respiratory diseases and helps to understand what types of diseases dinosaurs were susceptible to.” The team suspects the sauropod likely suffered flu- or pneumonia-like symptoms: cough, fever, and difficulty breathing, and eventually weight loss. Since aspergillosis in birds is often fatal if left untreated, the disease could also have led to Dolly’s early death.
Woodruff concludes, “When you hold your hands on these anomaly-marked bones and given the probable symptoms this animal suffered, you can’t help but feel sorry for Dolly,” the paleontologist says. “We’ve all experienced similar symptoms of illness – and here we have a 150-million-year-old dinosaur that probably felt just as miserable as we do when we’re sick.”
Source: Ohio University, professional article: Scientific Reports, doi: 10.1038/s41598-022-05761-3