Turtles didn’t always have shells and during the Triassic period, about 240 million years ago, a shell-like turtle has been found with bone cancer, likely the oldest case of such illness found in reptiles, birds and mammals, according to a new study published this week.
Researchers say finding cancer in ancient bones is a rare phenomenon, and it’s not because cancer didn’t exist. But to locate bone cancer in fossils, X-rays are required.
Fossilized remains found in quarry in 2013
In the journal JAMA Oncology researchers from the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania and the Leibniz Institute for Research on Evolution and Biodiversity in Berlin, Germany studied the fossilized left femur of the shell-less turtle called Pappochelys rosinae.
Pappochelys rosinae is an ancestor of modern-day turtles — other previously-found fossils suggested the reptile was only 8 inches long (20 centimeters), adorned with broad trunk ribs and had no shell. (Fully shelled turtles didn’t appear until about 205 million to 210 million years ago, at least according to the fossil record).
The bone belonging to the Pappochelys rosinae was discovered in a quarry in southwestern Germany in 2013.
Ancient find of bone cancer could be oldest ever
X-ray images found a mass in a layer of the bone called the periosteum. Infection and cancer can appear the same, but in an infection, pus is usually found in pores, which wasn’t noticed in the bone of the shell-less turtle.
Instead, what it looked like was a malignant periosteal osteosarcoma, a type of bone cancer, making it likely the oldest instance found in an Triassic amniote, meaning a reptile, bird or mammal, the team reported.
Paleopathology, the study of ancient disease, is a vital way by which we understand the evolution of pathogens, immune systems, healing physiology, and ultimately the environment.
Interestingly, the bone cancer found in the ancient turtle is similar to the bone cancer diagnosed today.
The prevalence of cancer in the tree of life is certainly interesting, but its antiquity should be regarded with equal interest considering the increase in human cancer, which has been related to environmental and genetic changes, and the extreme rarity of cancer in the fossil record