Researchers Uncover Car-Sized Sea Turtle Fossils From Dinosaur Era

by Lauren Boisvert
(Photo by Jordi Salas/Getty Images)

Thursday, Nov. 17, researchers found a fossil of Europe’s biggest turtle from the Cretaceous Period. It’s about the size of a Mini Cooper, and found in northeastern Spain. Leviathanochelys aenigmatica lived at the tail end of the dinosaur era, about 83 million years ago. It was about 12 feet long and weighed just under two tons.

According to a report from Reuters, the leatherback turtle, at about 7 feet, is today’s largest turtle. But the leviathanochelys aenigmatica completely dwarfed the leatherback. But, there is a turtle that outdoes the leviathanochelys aenigmatica: the Archelon, which lived 70 million years ago and grew to about 15 feet.

Albert Sellés of the Institut Català de Paleontologia in Barcelona, and co-author of the fossil study, compared the sizes of these Cretaceous turtles to cars. “Leviathanochelys was as long as a Mini Cooper while Archelon was the same size as a Toyota Corolla,” said the paleontologist. Extremely scientific measurements, I’m sure. But, helpful for visualization all the same.

In the ancient Tethys Sea, leviathanochelys aenigmatica had to deal with the 50-foot mosasaurs. Additonally, there were sharks, rays, and plesiosaurs that lurked in the waters.

“Attacking an animal of the size of Leviathanochelys possibly only could have been done by large predators in the marine context,” said Oscar Castillo, a master’s student in paleontology at Universitat Autònoma de Barcelona and the lead author of the fossil study. “At that time, the large marine predators in the European zone were mainly sharks and mosasaurs.”

“During the Cretaceous, there was a tendency in marine turtles to increase their body size,” Castillo added. “Leviathanochelys and Archelon might represent the apex of this process. The reason for this increase in body size has been hypothesized to be predatory pressures, but there might be other factors.”

Paleontologists Find Fossil of Huge Cretaceous-Era Turtle

Leviathanochelys and Archelon aren’t the only huge ancient turtles, though. There’s also the Cretaceous Period turtle Protostega and the Miocene Epoch turtle Stupendemys. They both reached about 13 feet. Protostega lived about 85 million years ago, while Stupendemys lived 7 to 13 million years ago.

The current fossil was unearthed in the Coll de Nargó village in Catalonia’s Alt Urgell county. A hiker in the Southern Pyrenees mountains spotted some of the fossils protruding from the ground and contacted experts. So far, paleontologists have found the posterior portion of its shell, and much of the pelvic girdle, according to Reuters, but no skull or tail.

According to the study, there were bony protrusions on the pelvis which researchers believe means that the leviathanochelys could have been its own singular lineage. The fossils differ from any other known sea turtle. Researchers also believe that the curious pelvic shape could have something to do with its respitory system.

“Some pelagic [living in the open ocean] animals show a modification in their respiratory system to maximize their breathing capacity at great depths,” said Sellés, positing that theory.