Megalonyx jeffersonii, or Jefferson's ground sloth, is an extinct species of giant ground sloth that lived from the Illinoian
Stage during the Middle Pleistocene through to the Rancholabrean of the Late Pleistocene (10,000 BC). Its closest living relatives
are the two-toed tree sloths of the genus Choloepus. This species ranged widely in North America. It belongs to the genus
Megalonyx, a name proposed by Thomas Jefferson — future president of the United States — in 1797.
