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".
Orangutan
Genomic comparisons show that the Tapanuli orangutan separated from the Sumatran orangutan about 3.4 million years ago. The Tapanuli orangutan separated from the Bornean orangutan much later, about 670,000 years ago. The orangutans are the only surviving species of the subfamily Ponginae, which also included several other species, such as the three extinct species of the genus "Gigantopithecus", including the largest known primate, "Gigantopithecus blacki". The ancestors of the Ponginae split from the main ape line in Africa 16 to 19 million years ago (Mya) and spread into Asia.