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".
List of fossil primates
The order Primates, established by Linnaeus in 1758, includes humans and their immediate ancestors. However, contrarily to the common opinion, most primates do not have especially large brains. Brain size is a derived character, which only appeared with genus "Homo", and was lacking in the first hominid. In fact, hominid encephalization quotient is only 1.5 Ma more recent than that of some dolphin species. The encephalization quotient of some cetaceans is therefore higher than that of most primates, including the nearest relatives of humans, such as "Australopithecus".