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".
Elephant
At the beginning of the Pleistocene, elephantids experienced a high rate of speciation. The Pleistocene also saw the arrival of "Palaeoloxodon namadicus", the largest terrestrial mammal of all time. "Loxodonta atlantica" became the most common species in northern and southern Africa but was replaced by "Elephas iolensis" later in the Pleistocene. Only when "Elephas" disappeared from Africa did "Loxodonta" become dominant once again, this time in the form of the modern species. "Elephas" diversified into new species in Asia, such as "E. hysudricus" and "E. platycephus"; the latter the likely ancestor of the modern Asian elephant. "Mammuthus" evolved into several species, including the well-known woolly mammoth. Interbreeding appears to have been common among elephantid species, which in some cases led to species with three ancestral genetic components, such as the straight-tusked elephants. In the Late Pleistocene, most proboscidean species vanished during the Quaternary glaciation which killed off 50% of genera weighing over worldwide.