We often think of dinosaurs as nearly invincible. Many were big, plenty had rough hides of scales, and their kind dominated the planet for over 130 million years, making them loom like impervious monsters in our imagination. But they suffered from bumps, scrapes and diseases just as today’s animals do. In fact, a dinosaur tail bone from Brazil is a reminder that these giants even suffered from tumours.

Unearthed back in 2012 in the country's southern São Paulo state, the bone wasn’t enough to go on for a definitive ID, so no one knows exactly what species the fossil belonged to. But from its anatomy, paleontologist Fernando Henrique de Souza Barbosa and colleagues have identified the specimen as belonging to one of the titanosaurs, the heavy-bodied, long-necked herbivores that included the largest animals ever to walk the earth. 

A single tail bone wouldn’t usually be much to fuss over, but this particular find showed something that's rarely seen in fossils. The bone, 93 to 83 million years old, was pocked with an outgrowth of unusual tissue.

CT scans and an examination of its microscopic structure showed that the "button-shaped protuberance" on the tail vertebrae wasn't just a strange area of bone growth – it also appeared to be attributed to what doctors know as osteoma and hemangioma, two forms of tumours.

The bump probably wouldn’t have bothered the dinosaur much. The researchers concluded that, based on their structure, the tumours were benign and the lump was so small that the giant animal was unlikely to have felt any difference at all as it swung its tail around. As far as the titanosaur was concerned, the osteoma might as well have not been there. 

Dinosaur experts have found this variety of strange bone growth before in the remains of hadrosaurs (the “duck-billed” dinosaurs), but this is the first time an osteoma has been documented in a titanosaur. Part of reason for that might be because palaeontologists haven’t spent much time looking.

The oldest known cases of cancer go back over 298 million years, and dot the fossil record here and there in groups ranging from crocodiles to whales, so there are certainly more cases waiting to be diagnosed. Too bad we’re over 66 million years too late to help such dinosaurs with their ailments.

Dinosaur Skeleton Related Content 2016 02 24


Top header image: Peter Eimon, Flickr