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".
Archaeoindris
Since its discovery, size estimates have varied from "larger than a human" to "possibly the largest primate ever". In a study by Jungers from 1990, the area of its molar teeth predicted a mass of , while the femoral head diameter predicted a mass of . In 1995, Laurie Godfrey estimated a mass of using the midshaft circumferences of the humerus and femur. Based on multiple regressions of the cortical area of the femur in 2008, Jungers and colleagues generated the current best estimate of with a possible range of . These estimates were considered to be more accurate since the harder cortical bone in the midshaft of the femur supported an animal's weight, and its thickness better correlated with the animal's mass than the midshaft diameter (which includes both hard cortex and spongy bone). The only fossil primate that was probably larger than "Archaeoindris" was "Gigantopithecus blacki", a close relative of orangutans.