of apes. The same study calculated a divergence time between the Ponginae and African great apes about 26–17.7 million years ago. Cladogram according to Zhang and Harrison, 2017: "G. bilaspurensis" In 1969, an 8.6 million year old mandible from the Sivalik Hills in northern India was classified as "G. bilaspurensis" by palaeontologists Elwyn L. Simons and , who believed it was an the ancestor of G. blacki. This bore resemblance to a molar discovered in 1915 in the Pakistani Pothohar Plateau then classified as "Dryopithecus giganteus". Von Koenigswald reclassified "D. giganteus" in 1950 into its own genus, Indopithecus, but this was changed again in 1979 to "G. giganteus" by American anthropologists Frederick Szalay and Eric Delson until Indopithecus was resurrected in 2003 by Australian anthropologist David W. Cameron. "G. bilaspurensis" is now considered a synonym of Indopithecus giganteus, leaving Gigantopithecus monotypic (with only one species), G. blacki. Description Size Total size estimates are highly speculative because only tooth and jaw elements are known, and molar size and total body weight do not always correlate, such as in the case of post-canine megadontia hominins (small-bodied primate exhibiting massive molars and thick enamel). In 1946, Weidenreich hypothesised that Gigantopithecus was twice the size of male gorillas. In 1957, Pei estimated a total height of about . In 1970, Simons and American palaeontologist Peter Ettel approximated a height of almost and a weight of up to , which is about 40% heavier than the average male gorilla. In 1979, American anthropologist Alfred E. Johnson Jr. used the dimensions of gorillas to estimate a femur length of and humerus length of for Gigantopithecus, about 20–25% longer than those of gorillas. In 2017, Chinese palaeoanthropologist Yingqi Zhang and American anthropologist Terry Harrison suggested a body mass of , though conceded this was likely an overestimate and it is impossible to obtain a reliable body mass estimate without more complete remains. The average maximum length of the upper canines for presumed males and females are and , respectively, and Mandible III (presumed male) is 40% larger than Mandible I (presumed female). These imply sexual dimorphism, with males being larger than females. Such a high degree of dimorphism is only surpassed by gorillas among modern apes in canine size, and is surpassed by none for mandibular disparity. Teeth and jaws Like other apes, Gigantopithecus had a dental formula of , with two incisors, one canine, two premolars,