Eastern gorilla
Grauer's gorillas and mountain gorillas were previously thought to be two of the three subspecies of one single species, the gorilla ("Gorilla gorilla"). However, genetic research has shown that the two eastern subspecies are far more closely related than the western subspecies: the western lowland gorilla ("G. gorilla gorilla"), which justified the separate classification. The two eastern subspecies are now classified as "G. beringei".
Megatherium
"Megatherium" is one of the largest land mammals known to have existed, weighing up to 4 tonnes and measuring up to in length from head to tail. It is the largest-known ground sloth, as big as modern elephants, and would have only been exceeded in its time by a few species of mammoth. The group is known primarily from its largest species, "M. americanum". "Megatherium" species were members of the abundant Pleistocene megafauna, large mammals that lived during the Pleistocene epoch.