Paleontologists in Argentina unearthed a rare skull of the extinct mega-ground sloth -- Megatherium americanum, dating back to approximately 3.58 million years ago.
The Megatherium americanum, or "Great Beasts from America," is one of the first specimens of the colossal mammals first discovered in 1787 by Manuel Torres on the Lujan River, Argentina.
It was then shipped to the Muse Nacional de Ciencias in Madrid, where its original skeleton is still on display to this day for public viewing.
Colossal Ground Sloths
In prehistoric America, Giant Ice Age ground sloths roamed the wilds, while its descendants are the much smaller tree sloths we know today.
One of the largest of these slow-moving ground sloths was the Megalonyx jeffersonii or 'Great Claw' that reached almost 10 feet in height and would surely intimidate ancient human hunters.
Megatheriums are one of a number of giant ground sloth species that thrived in South America in the Early Pliocene epoch roughly 5 million years ago until the end of the Pleistocene epoch 11,700 years ago.
Scientists determined that the earliest and tiniest known species is the Megatherium altiplanicum from Bolivia.
The gentle-clawed herbivores first appeared roughly 35 million years ago in South America but would later perish with other colossal Ice Age mammals such as the mastodons, dire wolves, wooly rhinos, cave lions, and saber-toothed tigers.
Dr. Nicolas Chimento front he Museo Argentino de Ciencias Naturals says, "Megatherium remains are very common in almost the entire Argentine territory, however, it is the first time that the remains of such high antiquity have been found, which is only comparable to a find made a years ago in Bolivia."
Details of the discovery by Chimento and his team were presented to the Journal of South American Earth Sciences.
The King of Giant Sloths
Despite the gigantic ground sloths being commonplace in prehistoric South America, the Megatherium americanum that stood nearly the size of bull elephants was the true king of giant sloths.
Native to Argentina, Bolivia, and Uruguay during the Pleistocene epoch it was 10-times the size of sloths today and weighed roughly 3-4 tons. The fully adept mammals stood and walked on their hind legs reaching heights of 12-13 feet and were, by far, the largest bipedal mammal that lived.
The new perfectly preserved partial skull of the king of giant sloths was found in the vicinity of San Eduardo del Mar, Buenos Aires that is said to belong to a large juvenile ground sloth.
Researchers note that this is the first undoubted record of Megatherium from the Pliocene of Argentina, the oldest records for the genus.
The recent findings blur previous bio-geographical proposals sustaining that the genus originated in the High Andes that later disperse to the lowlands.
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