| Method |
Researchers take the minimum constraint on the human-macaque split as 23.5 Ma, based on the oldest record of Proconsul, biostratigraphy and external dating (the first record of the long-ranging hominoid genus Proconsul is from Meswa Bridge in Kenya, biostratigraphically constrained to c. 23.5 Ma (Pickford and Andrews 1981 Tassy and Pickford 1983)). The soft maximum constraint is based on members of the stem of Catarrhini, namely the families Propliopithecidae (Propliopithecus, Aegyptopithecus) and Oligopithecidae (Oligopithecus, Catopithecus) that are basal to the cercopithecoid-hominoid split (Rasmussen 2002). These are represented in particular from the rich Fayûm beds in Egypt, dated as early Oligocene (33.9 – 28.4 Ma ± 0.1 Myr). |