Researchers in South America claim to have discovered the fossilized remains of a one-ton beast of a rodent that thrived in the forests and estuaries of the continent four million years ago. The giant skull of the Josephoartigasia monesi was found on the coast of Rio de La Plata in Uruguay in a broken boulder.

Researchers Andres Rinderknecht of the Museum of Natural History and Ernesto Blanco of the Institute of Physics studied the fossil in Montevideo. J. Monesi's skull was a massive 53 centimeters long, and scientists used this to determine that the size of the rodent was about 1-ton, or the size of a small car.

"We report the discovery of an exceptionally well preserved fossil skull of a new species of rodent, by far the largest ever recorded," said the scientists in the 'Proceedings of the Royal Society, Biological Sciences' journal.

"The creature itself weighed between one and 1.4 tons. Its skull is half-a-metre long and reached a length of around three metres, assuming its body was barrel-shaped like that of a capybara. The incisors of the mega rodent were around four inches and characteristics of its teeth suggest that it dined on aquatic plants, perhaps even fruit," said Dr. Blanco.

Rodents account for four in every ten species of mammal, however, they are typically pretty small in size. Most rodents are less than one kg (2.2lbs). The largest known rodent until now was the capybara, which reaches about 132 pounds. But even the capybara is considered a lightweight compared to this new variation.