Paleontologists have discovered fossilized remains of a 60-million-year-old South American giant turtle that lived in what is now Colombia.
The giant creature was named Carbonemys cofrinii or “coal turtle,” because it was discovered in 2005 in a coal mine that was part of northern Colombia’s Cerrejon formation. It belongs to a group of side-necked turtles known as pelomedusoides.
The specimen’s skull measures 24 cm, its shell which was recovered nearby – and is believed to belong to the same species – measures some 172 cm (about 5 feet 7 inches) long.
“We had recovered smaller turtle specimens from the site,” said Edwin Cadena, a doctoral student at North Carolina State University, who discovered the fossil. “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 gigantism in freshwater turtles.”
Smaller relatives of C. cofrinii 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.
The paleontologists 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 paleontologist 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,” said Dr Ksepka, a co-author of a paper in the Journal of Systematic Palaeontology describing the find. “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.”