Carbonemys roamed the Earth around the same time as the 40-foot Titanoboa, about 60 million years ago, during the late Paleocene, in the region that is now northern Colombia. In that era, reptiles were the dominant creatures on Earth.
Carbonemys cofrinii was big by modern-day standards, and a team of paleontologists, led by Edwin Cadena and Daniel Ksepka, recently published their discovery in the Journal of Systematic Palaeontology about finding the creature’s skull. C. cofrinii was the size of a small car, and its skull was about 10 inches long. The fossilized carapace found nearby measures 5’7″ in length.
While this doesn’t make C. cofrinii the biggest turtle of all, it was still large enough to prey upon other inhabitants of the Paleocene swamp. It might have been an enormous ambush predator, feasting on small crocodilians and other smaller animals.
It’s hoped that future analysis will allow paleontologists to understand the turtle’s natural history. It’s also somewhat perplexing that there were so many large reptiles in the same area. One hypothesis entails that the growth of these reptiles is due to the warmer climate of the region, making them balloon to cope with the hothouse world. Then again, the largest turtles, panpelomedusidae, are present in the fossil record during a much cooler period.
There might be some yet unknown ecological influences. The creature was most probably an omnivore, feasting on anything from mollusks to crocodilians to sate itself.
Reference: “New pelomedusoid turtles from the late Palaeocene Cerrejón Formation of Colombia and their implications for phylogeny and body size evolution” by Edwin A. Cadena, Daniel T. Ksepka, Carlos A. Jaramillo and Jonathan I. Bloch, 17 May 2012, Journal of Systematic Palaeontology.