A team of experts from Germany, Canada, and the United States worked together in order to diagnose a 240 million-year-old Pappochelys rosinae, the oldest known turtle.
Upon analysis, they found that the ancient creature suffered from a type of rare bone cancer called periosteal osteosarcoma. A fossilized tumor was found in the hind legs of the animal, a similar symptom that is also seen in humans diagnosed with the disease.
"This is one of the oldest cases of cancer in the fossil record of vertebrates, and the oldest case in an amniote, which is the group that encompasses reptiles, birds and mammals," stated Florian Witzmann, a co-author of the study.
The findings appear in JAMA Oncology.
A 240 Million Year Old Tumor
The tumor was an incredible find not because cancer in ancient creatures were unusual. In fact, scientists believe that the disease was as common back in the day as it is now. The problem is, cancer in fossils is difficult to identify.
The disease is the abnormal growth of cells in the soft tissues as well as the hard tissues (like the bone). However, soft tissues very rarely appear in the fossil record. Therefore, the diagnosis of diseases from ancient times is limited to what is left behind: the hard tissues.
To diagnose the ancient turtle, the researchers used microscopy and computerized tomography, a type of X-ray. The process revealed a mass in the layer of the bone called the periosteum.
The researchers eliminated the possibility that it was an infection due to the absence of pores where puss would have oozed out. They also noted that periosteal osteosarcoma has previously been reported in an amphibian that lived during the Triassic period.
"Our finding provides further evidence that cancer is not restricted to the modern human physiology," stated Yara Haridy from the Museum für Naturkunde Berlin and lead author of the study. "Instead, the susceptibility to this disease roots far back in the evolutionary history of vertebrates, hundreds of millions of years before the origin of humans."
The Pappochelys is an ancestor of modern-day turtles. They walked the Earth around the Triassic period when the first dinosaurs started to appear.
The discovery of the Pappochelys provided crucial information about the evolution of turtles. Millions of years ago, the creatures had broad trunk ribs, but no shell.
Remains of the ancient turtle were unearthed at the Schumann Quarry in southwestern Germany in 2015.