THE FOSSILS of giant turtles twice the size of a human and 100 times heavier than their closest relative have been discovered in South America.

The huge shells would have belonged to turtles that lived in a humid swamp five to ten million years ago.

Stupendemys geographicus is an ancient species of turtle that was first described by academics in the mid-1970s.

Researchers from the University of Zurich along with experts from Colombia, Venezuela, and Brazil have recently found impressive specimens of this extinct creature in new locations across Venezuela and Colombia.

Study leader Marcelo Sánchez said: “The carapace of some Stupendemys individuals reached almost three meters, making it one of the largest, if not the largest turtle that ever existed.”

Experts have estimated the turtle’s body mᴀss at 1,145kg, which is almost 100 times larger than the big-headed Amazon river turtle, its closest living relative.

The researchers noticed that some of the shells had horns.

Sánchez said: “The two shell types indicate that two Sєxes of Stupendemys existed – males with horned shells, and females with hornless shells.”

This is apparently the first example of Sєxual dimorphism or clear visual differences between the Sєxes of side-necked turtles ᴅᴇᴀᴅ or alive.

The fossils also had bite marks and evidence of punctured bones, suggesting they still had predators despite their huge size.

The new discoveries have indicated that these giant creatures lived across a much larger area of South America than previously thought.

They have also helped scientists piece together more of the turtle evolutionary tree.

Sánchez concluded: “Based on studies of the turtle anatomy, we now know that some living turtles from the Amazon region are the closest living relatives.”