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".
Largest organisms
The largest land mammal extant today is the African bush elephant. The largest extinct land mammal known was long considered to be "Paraceratherium orgosensis", a rhinoceros relative thought to have stood up to tall, measured over long and may have weighed about 17 tonnes. In 2015, a study suggested that one example of the proboscidean "Palaeoloxodon namadicus" may have been the largest land mammal ever, based on extensive research of fragmentary leg bone fossils from one individual, with a maximum estimated size of 22 tonnes.