Alcelaphines (the hartebeest-wildebeest-blesbok group) appear about 5 million years (VRBA, E. S. 1979), and there is an increase in alcelaphines with the Pleistocene, for example at younger sites in the Chemeron formation, Tugen Hills, Kenya, in the interval from 2.73–2.63 My and after 2.5 My (Goble, E.D. 2011), and this is a result of an increase in ecological niches for grazing animals, extensive open savanna grasslands began to spread out in the Pleistocene (Janis, C. 2008) as the Homo lineage used fire from natural resources such as volcanoes along the East African Rift to burn down forest (Nygren, J. 2017), re-creating the open grassland on the coast of Danakil where they had speciated (Nygren, J. 2018).

Synapses

VRBA, E. S. (1979). Phylogenetic analysis and classification of fossil and recent Alcelaphini Mammalia: Bovidae. Biological Journal of the Linnean Society, 11(3), 207–228. https://doi.org/10.1111/j.1095-8312.1979.tb00035.x

Goble, E.D. 2011. Skeletal element and bovid abundance analyses in paleoenvironmental reconstruction of the Chemeron Formation, Tugen Hills, Kenya. (Society of Vertebrate Paleontology Meetings, Las Vegas, NV, USA.)

Janis, C. (2008). An Evolutionary History of Browsing and Grazing Ungulates. In Ecological Studies (pp. 21–45). Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-540-72422-3_2

Nygren, J. (2017). The Homo lineage created the savanna, rather than the other way around, https://steemit.com/anthropology/@johan-nygren/the-homo-lineage-created-the-savanna-rather-than-the-other-way-around

Nygren, J. (2018). On the Origin of the Species, Danakil as the Galapagos of Pliocene East Africa, https://gist.github.com/resilience-me/1ee3b88c977ec5f8f46e08ffe42fd92a