"Gigantopithecus" is now classified in the subfamily Ponginae, closely allied with "Sivapithecus" and "Indopithecus". This would make its closest living relatives the orangutans. However, there are few similar traits (synapomorphies) linking "Gigantopithecus" and orangutans due to fragmentary remains, with the main morphological argument being its close affinities to "Sivapithecus", which is better established as a pongine based on skull features. In 2017, Chinese palaeoanthropologist Yingqi Zhang and American anthropologist Terry Harrison suggested that "Gigantopithecus" is most closely allied to the Chinese "Lufengpithecus", which went extinct 4 million years prior to "Gigantopithecus".