The first serious evidence of an infectious pathology in non-avian dinosaurs has been discovered. In any case, this is revealed by the study published in the journal Scientific Reports, concerning an animal dating from the golden age of the dinosaurs, 145 million years ago.
The animal was a large herbivorous sauropod with a long neck answering to the scientific name of “MOR 7029”, and the nickname of “Dolly”. Its fossilized remains were discovered in 1990 in Montana in the United States. Examining “Dolly’s” neck bones years later, paleontologist Cary Woodruff identified bony protrusions of unusual shape and texture. “It was really weird, I had never seen that in any dinosaur,” confesses to AFP this sauropod specialist, lead author of the study. What put him on the track? The abnormal protrusions located down the animal’s neck, right at the intersection of the air sacs, air-filled sacs connected to the lungs – a feature of the respiratory systems unique to dinosaurs and birds. CT imaging then scanned inside the bones, confirming an abnormality that most likely formed secondary, in response to an air sac infection.
A micro-fungal disease?
Difficult for all that to make a diagnosis, since there remains no biological trace of these tissues. So the scientists went to investigate Dolly’s closest living descendants: the birds. “Since birds are dinosaurs, this was an approach that made sense from an evolutionary perspective,” explains Cary Woodruff. His team, also made up of veterinarians, observed pathologies in birds producing the same bone symptoms. In particular a disease with similar characteristics: aspergillosis, a fungal respiratory infection. “In birds, it is the most widespread respiratory infection which, from an evolutionary point of view, must come from somewhere,” underlines the paleontologist. Dolly lived in a hot and humid climate, an environment conducive to fungal infections, adds the researcher, who excludes a viral disease such as bird flu, because “it does not attack bones in the same way”. Aspergillosis causes flu-like symptoms like fever, headache, sneezing and coughing. It can be fatal if left untreated.
“Dolly must have felt very bad, imagines Cary Woodruff. It may have killed it, or weakened it, making it easy prey for predators like the dreaded T-rex.