'Smart car' size turtle fossil discovered in Colombia

Palaeontologists from North Carolina State University have found the fossilized remains of a 60-million-year-old South American giant that lived in what is now Colombia

The turtle in question is Carbonemys cofrinii, which means “coal turtle,” and is part of a group of side-necked turtles known as pelomedusoides.

The fossil was named Carbonemys because it was discovered in 2005 in a coalmine that was part of northern Colombia’s Cerrejon formation.

The specimen’s skull measures 24 centimetres, roughly the size of a regulation NFL football. The shell that was recovered nearby - and is believed to belong to the same species - measures 172 centimetres, or about 5 feet 7 inches, long.

That’s the same height as Edwin Cadena, the NC State doctoral student who discovered the fossil

“We had recovered smaller turtle specimens from the site. But after spending about four days working on uncovering the shell, I realised 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 said

Smaller relatives of Carbonemys existed alongside dinosaurs. But the giant version appeared five million years after the dinosaurs vanished, during a period when giant varieties of many different reptiles – including Titanoboa cerrejonensis, the largest snake ever discovered – lived in this part of South America.

Researchers believe that a combination of changes in the ecosystem, including fewer predators, a larger habitat area, plentiful food supply and climate changes, worked together to allow these giant species to survive. Carbonemys’ habitat would have resembled a much warmer modern-day Orinoco or Amazon River delta

In addition to the turtle’s huge size, the fossil also shows that this particular turtle had massive, powerful jaws that would have enabled the omnivore to eat anything nearby – from mollusks to smaller turtles or even crocodiles

Thus far, only one specimen of this size has been recovered

Dr Dan Ksepka, NC State palaeontologist and research associate at the North Carolina Museum of Natural Sciences, believes that this is because a turtle of this size would need a large territory in order to obtain enough food to survive.

“It’s like having one big snapping turtle living in the middle of a lake. That turtle survives because it has eaten all of the major competitors for resources. We found many bite-marked shells at this site that show crocodilians preyed on side-necked turtles. None would have bothered an adult Carbonemys, though – in fact smaller crocs would have been easy prey for this behemoth,” said Ksepka, co-author of the paper describing the find

The palaeontologists’ findings appear in the Journal of Systematic Palaeontology.