One of the largest turtles that ever lived inhabited the lakes and rivers of north and south American between 7 and 13 million years ago, was almost as big as a car. Scientists from Switzerland say they have uncovered new fossils of the turtle called, Stupendemys Geographicus, in Colombia's Tatacoa Desert and Venezuela's Urumaco region.
For the first time, scientists are able to provide a comprehensive profile of the big reptile, which was up to 4 metres long and 1.13 tonnes in weight.
Stupendemys, which means “stupendous turtle” inhabited a colossal wetlands system spanning what is now Colombia, Venezuela, Brazil and Peru before the Amazon and Orinoco rivers were formed.
The team of paleobiologists from the University of Zurich say that the Stupendemys Geographicus turtle was over one hundred times heavier than its closest relative, the Amazon river turtle (Peltocephalus dumerilianus) and twice the size of the largest living sea turtle, the leatherback turtle (Dermochelys coriacea).
A giant prehistoric turtle
Marcelo Sánchez-Villagra, director of the University of Zurich's Palaeontology Institute and Museum said in a statement, "Stupendemys Geographicus is one of the largest turtles, if not the largest that has ever existed."
Fossils of the Stupendemys Geographicus turtle were first discovered in the 1970s, but many questions remained about this animal. The new fossils included the largest-known turtle shell – 9.4ft (2.86 meters) long – and the first lower jaw remains, which gives scientists clues about its diet.
These new remains also tell scientists that Stupendemys males had sturdy front-facing horns on both sides of its shell very close to the neck. Deep scars discovered in the fossils indicated that these horns may have been used like a weapon for fighting with other Stupendemys males over mates or territory. Females did not have horns.
In many areas, the appearance of Stupendemys also coincides with the emergence of Purussaurus, an extinct species of giant caiman (crocodile like creature) that was around 11-13 metres long. Scientists say it was probably a predator of the giant turtle, after an analysis of bite marks and punctured bones found on the shells of the giant turtle fossils.
Reference: E.-A. Cadena at Universidad del Rosario in Bogotá, Colombia al., "The anatomy, paleobiology, and evolutionary relationships of the largest extinction side-necked turtle," Science Advances (2020). DOI: 10.1126/sciadv.aay4593, https://advances.sciencemag.org/content/6/7/eaay4593