Papionin dispersal patterns largely mirror those of early hominins (Gilbert C.C., 2008), radiating from the Afar region and outwards throughout East Africa and down to South Africa, which would be expected if the spread of grasslands followed the migration of Homo, the animal that specialized in the manipulation of their environment, and that could attain fire as a natural resource from volcanoes around Lake Turkana (livescience.com, 2015). Gelada and baboons can interbreed in the wild (Dunbar, R. I. M, 1994) which means that adaptations that developed in one clade on the coastal grassland of Danakil, where 40% of the mammal fauna at Woranso-Mille are papionins (Haile-Selassie et al., 2007), found alongside other grass eaters like horses (Bernor, R. L., 2013) and antelopes (Vrba, E. S., 2006), and where adaptation towards grass-eating can be seen in papionins as well as in hominins (Levin, N. E., 2015) like Paranthropus deyiremeda, could spread to other clades.

Synapses

Gilbert C.C. (2008). African Papionin Phylogenetic History and Plio-Pleistocene Biogeography

2015, December 28. Volcanoes Sparked an Explosion in Human Intelligence, Researcher Argues. Retrieved from https://www.livescience.com/53213-lava-flows-sparked-human-fire-use.html

Dunbar, R. I. M., & Dunbar, P. (1974). On hybridization between Theropithecus gelada and Papio anubis in the wild. Journal of Human Evolution, 3(3), 187–192. https://doi.org/10.1016/0047-2484(74)90176-6

HAILE-SELASSIE, Y., DEINO, A., SAYLOR, B., UMER, M., & LATIMER, B. (2007). Preliminary geology and paleontology of new hominid-bearing Pliocene localities in the central Afar region of Ethiopia. Anthropological Science, 115(3), 215–222. https://doi.org/10.1537/ase.070426

Bernor, R. L., Gilbert, H., Semprebon, G. M., Simpson, S., & Semaw, S. (2013). Eurygnathohippus woldegabrieli, sp. nov. (Perissodactyla, Mammalia), from the middle Pliocene of Aramis, Ethiopia. Journal of Vertebrate Paleontology, 33(6), 1472–1485. https://doi.org/10.1080/02724634.2013.829741

Vrba, E. S. (2006). A possible ancestor of the living waterbuck and lechwes: Kobus basilcookeisp. nov. (Reduncini, Bovidae, Artiodactyla) from the Early Pliocene of the Middle Awash, Ethiopia. Transactions of the Royal Society of South Africa, 61(2), 63–74. https://doi.org/10.1080/00359190609519954

Levin, N. E., Haile-Selassie, Y., Frost, S. R., & Saylor, B. Z. (2015). Dietary change among hominins and cercopithecids in Ethiopia during the early Pliocene. Proceedings of the National Academy of Sciences, 112(40), 12304–12309. https://doi.org/10.1073/pnas.1424982112