When we’re thinking about nowadays turtles, we often forget how huge these can get. We often think about cute little turtles heading towards the ocean we’re being shown footages on National Geographic. But we forget that some 66 million years ago, animals were quite different. For instance, have you ever imagined a turtle as big as your car, that could have fed with crocodiles?
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 coal mine that was part of northern
Colombia’s Cerrejon formation. The specimen’s skull measures 24
centimeters, roughly the size of a regulation NFL football. The shell
which was recovered nearby – and is believed to belong to the same
species – measures 172 centimeters, 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 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.
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.