Ouranopithecus

Based on O. macedoniensis' dental and facial anatomy, it has been suggested that Ouranopithecus was actually a dryopithecine. However, it is probably more closely related to the Ponginae.^[5][6] Some researchers consider O. macedoniensis to be the last common ancestor of humans (hominins) and the other apes,^[7] and a forerunner to australopithecines and humans,^[8] although this is very controversial and not widely accepted. It is true that O. macedoniensis shares derived features with some early hominins (such as the frontal sinus, a cavity in the forehead), but they are almost certainly not closely related species.^[9]

In 1984, British palaeontologists Peter Andrews and Lawrence B. Martin classified Graecopithecus and Ouranopithecus as synonyms (same taxon) and treated them as members of the genus Sivapithecus.^[4][10] However, comparative analysis showed that there is not enough data to support the synonymy.^[11]

When more O. macedoniensis fossils were discovered^[12] including part of the skull in the 1990s,^[13] it became apparent that O. macedoniensis and G. freybergi are distinct species. In the light of new data, in 1997, Australian palaeontologist David W. Cameron treated Graecopithecus as a valid genus based on taxonomic priority and renamed O. macedoniensis as Graecopithecus macedoniensis.^[14][15] However, better O. macedoniensis specimens were found^[16] including a new species Ouranopithecus turkae from Turkey^[17] that warranted separation of the genus. Furthermore, a controversial paper in 2017 claimed that Graecopithecus is more closely related to hominins than to other great apes,^[18] which if true would clearly distinguish it from Ouranopithecus specimens. Separate genus for the two therefore continue to be generally adopted.^[19][20][21]