In a hot, humid Jurassic landscape full of plant and animal life in what is now southwestern Montana, a long-necked teenage dinosaur was terribly ill, with flu and pneumonia-like symptoms, likely feverish and tired. , with labored breathing, coughing, sneezing and diarrhea.
Some 150 million years later, the remains of that animal, nicknamed Dolly, represent the first known dinosaur with evidence of respiratory disease — abnormal growth of tissue that looks like fossilized broccoli in three bones in the neck, formed in reaction to an infection in the sacs. airways attached to your lungs.
Scientists said Thursday that the dinosaur appeared to be suffering from a fungal infection similar to aspergillosis, a common and often fatal respiratory disease for modern birds and reptiles that sometimes causes infection in the bones. The condition may have killed Dolly, they say.
Dinosaurs suffered from disease like any other animal, but there is little evidence in the fossil record because soft tissues are rarely preserved in a fossilization process that favors hard things like bones, teeth and claws. Pathologies such as broken and healed bones, tooth abscesses, blood infections affecting bones, arthritis and even bone cancer have already been found in dinosaur fossils.
Dolly belonged to a previously unknown species of sauropod dinosaur, a vegetarian group with long necks, long tails, small heads and four strong legs that included the largest land animals in Earth’s history.
Dolly, about 60 feet tall and weighing perhaps 4 to 5 tons, died aged 15 to 20, according to Cary Woodruff, director of paleontology at the Great Plains Dinosaur Museum in Malta, Montana, and lead author of the study. published in Scientific Reports.
Similar sauropods usually reached adulthood in their late thirties.
“Poor Dolly, she probably felt pretty bad with all the signs and symptoms of a lower respiratory infection that we also suffer from, like fever, tight chest, labored breathing and coughing up phlegm… uh!” said the anatomist and co-author. of the Lawrence Witmer study of the Ohio University College of Osteopathic Medicine.
“Was Dolly so sick that she couldn’t keep up with the herd? Did she die of this disease? Did she die alone? We know she was sick for a long time — it was a chronic illness — because she had it long enough for her bones to develop malignant reactive tissue.” “, said Witmer.
It is not uncommon for sick animals not to die directly from the disease, but being victims of predation or starvation, due to its debilitating effects.
“Yes, as scientists we are excited and intrigued by Dolly’s disease, but as humans we love dinosaurs and other animals. said Witmer.
Allosaurus fossils have been found in the same region.
Dolly’s remains were excavated in 1990 and 2013-2015. The scientific name of Dolly’s species will be revealed in a future study. The dinosaur looks like a close relative of the well-known Diplodocus.
The researchers don’t know Dolly’s gender, but they said the dinosaur was named after a famous singer.
“From Dolly Parton, of course,” said Woodruff.
Dolly’s dilemma not only sheds light on medical conditions in deep time, it offers insight into the anatomical structure of dinosaur lungs and air sacs.
Sauropods and carnivorous dinosaurs called theropods, a group that includes birds, have much more elaborate respiratory tracts than mammals, including humans. In addition to lungs, they have thin, balloon-shaped air sacs that invade their body cavity and many bones. In Dolly, the abnormal bone growths were present at the connection between respiratory tissue and the bones of three vertebrae, evidence that the infection had come from the lungs.
Aspergillosis, caused by inhaling spores of a fungus, is the most common respiratory infection today in birds, which evolved from Jurassic feathered theropods and are classified as a branch of the dinosaurs.
“I have not personally known any fossils for which I have felt such sympathy,” Woodruff said.
Translated by Luiz Roberto M. Gonçalves
