An artist's depiction of the giant freshwater turtle, Stupendemys geographicus,, which lived in the rivers and lakes of South America about 12 million years ago (Credit: Jaime Chirinos/www.media.uzh.ch)

Though it is now arid, the Urumaco region in Venezuela's Falcón State was once a mega wetland that was home to numerous colossal animal species. These included rodents the size of modern-day buffaloes and 10-foot (3-meter) tall carnivorous birds. The latest to join the list of the area's massive creatures is a giant turtle that was 100 times larger than its closest living relative, the Amazon river turtle, and about 1.5 times the size of the world's largest living turtle, the marine leatherback.