Earlier this year, Ph.D candidate Edwin Cadena revealed the fossilized remains of a giant ancient turtle – Carbonemys – which was roughly the size of a Smart car. Now he’s back with a new and completely different specimen: Puentemys, a turtle that lived 60 million years ago in what is now Colombia.
Puentemys would have been a contemporary of Cabonemys, although at approximately five feet long Puentemys isn’t quite as large as its fellow turtle. But the most unique feature of this turtle isn’t the size, it’s that the shell is almost perfectly round.
Being shaped like a breath mint may have been a lifesaver for the turtle in a couple of important ways, Cadena says. “The shape may have allowed Puentemys to increase its body temperature quickly, because more of the shell surface would have been exposed to the sun,” he says. It may also have made Puentemys too bitter a pill for certain predators to swallow. “It was also a good shape for escaping predators like the giant snake Titanoboa,” Cadena adds, “because even though boas can expand their mandibles, it would be very hard for a snake to swallow something extremely circular.”
Puentemys means “turtle from the bridge,” a reference to the area where it was found. The Bridge is the deepest pit in the Cerrejon formation, and the place where all of the formation’s vertebrate fossils – like Titanoboa and Carbonemys – were discovered.
Cadena’s findings appear in the July issue of the Journal of Paleontology.