Cancer can be defined as a complex set of diseases that is produced by an uncontrolled proliferation of cells, which causes what we know as a tumor. But this pathology is not exclusively human.
Last Monday, August 4, an investigation published a surprising finding: a sign of cancer in the bone of a dinosaur. But it is not a new fossil, but a discovery made in 1989, in the badlands of the Dinosaur Provincial Park of the Canadian province of Alberta. At the time, scientists assumed it was a malformed leg bone from a fracture.
But a new examination of this fossil piece has shown, more than 30 years later, something very different. Research results show that the malformation is a manifestation of osteosarcoma, an aggressive bone cancer. The dinosaur specimen is a Centosaurus , which lived 76 million years ago, during the Cretaceous period. It is a herbivorous dinosaur with a four-legged beak and about twenty feet long, which had a long horn on its nose and a bony ridge on its neck with two smaller hooked horns.
The animal had a fibula tumor larger than an apple, according to statements by paleontologist David Evans of the Royal Ontario Museum in Toronto, one of the researchers on the study published in the Lancet Oncology journal. Furthermore, this Centrosaurus was probably weak and limping before dying. “This remarkable finding shows that no matter how big or powerful some dinosaurs may seem, they were affected by many of the same diseases that we see in humans and other animals today , including cancer,” he adds.
Why haven’t we found out before?
If dinosaurs suffered from these types of pathologies, it is surprising not to have found them before in the fossil record that we have. But, because most tumors occur in soft tissues that do not easily fossilize , there is little or no prior evidence.
Nothing indicates that dinosaurs, like any other animal, had been exempt from suffering from cancer.
So how did scientists discover this osteosarcoma? The researchers confirmed it was a tumor using high-resolution CT scans and looking at thin sections under the microscope. “Not only were we able to show that the bone tissue exhibited the characteristics of osteosarcoma, but the tumor spiraled through the bony cortex , discounting its original identification of a healed fracture,” according to Evans.
And although weak and lame, this specimen most likely did not die of cancer. His body was found in a vast bone bed containing the remains of hundreds of Centrosaurus individuals, suggesting that they died as part of a herd caught in a flood. Although his cancer may have reduced his mobility to make him an attractive target for large predators, living in a large herd may have provided the Centrosaurus with security in its delicate situation as the cancer progressed.
