What’s the size of a Smart car and has a shell that could be used as a kiddie pool? If you answered Carbonemys cofrinii, or “coal turtle,” you would be correct. Paleontologists from North Carolina State University found the fossilized remains of the 60-million-year-old giant turtle in what is now Colombia.
Carbonemys was discovered in 2005 in a coal mine that was part of northern Colombia’s Cerrejon formation. Its skull is roughly the size of a regulation NFL football and its shell, which recovered nearby, is about 5 feet 7 inches, long–the same height as Edwin Cadena, the NC State doctoral student who discovered the fossil, according to a university press release.
“We had recovered smaller turtle specimens from the site. But after spending about four days working on uncovering the shell, I realized that this particular turtle was the biggest anyone had found in this area for this time period–and it gave us the first evidence of giantism in freshwater turtles,” Cadena says in the release.
Other varieties of giant reptiles were found around this time as well, five million years after the dinosaurs vanished, including Titanoboa cerrejonensis, the largest snake ever discovered. Researchers said conditions were just right to allow for these giant creatures to exist. Factors like abundant food, few predators, vast habitat, and climate change all worked together to allow them to grow to such sizes.
"The environment seems to have been tropical based on fossil plants found at the site," study researcher Dan Ksepka, of NC State told LiveScience. "And the turtle appears to have been adapted to spending most of its time in the water, though coming ashore to lay eggs would be part of its life cycle."
The turtle would have had powerful jaws allowing the omnivore to eat just about anything, even smaller crocodiles. And that all-encompassing diet is probably why no other turtle of this size has been found at the site.
"It's like having one big snapping turtle living in the middle of a lake," Ksepka said in the release. "That turtle survives because it has eaten all of the major competitors for resources."
This research will be detailed in the June 2012 print edition of the Journal of Systematic Paleontology and was funded by the Smithsonian Institute and the National Science Foundation.