A dinosaur that hobbled around some 76 million years ago has finally been diagnosed—with cancer, New Atlas reports. Researchers in Canada spotted a large growth in a Centrosaurus apertus leg bone and ran it through a battery of tests, making CT scans, constructing a cross-section, and cutting it into thin slices to analyze it at a cellular level under a microscope. Conclusion: The plant-eating dinosaur suffered from advanced osteosarcoma, a kind of cancer that still afflicts humans and other animals. "Here, we show the unmistakable signature of advanced bone cancer in 76-million-year-old horned dinosaur—the first of its kind," study co-author Mark Crowther tells Phys.org. "It's very exciting."
Advanced as it was, the cancer likely didn't kill the dinosaur—which was found in a huge bonebed with other Centrosaurus and probably died along with them. "The cancer would have had crippling effects on the individual and made it very vulnerable to the formidable tyrannosaur predators of the time," says study co-author David Evans. "The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it normally would have with such a devastating disease." Cancer has been found in other dinosaur fossils before, per Science, but the study says this is the first osteosarcoma diagnosis in a dinosaur. (Or see why the "smallest" dinosaur wasn't really a dinosaur.)