Ecological change in the lower Omo Valley around 2.8 Ma

A significant ecological shift occurred in the lower Omo Valley, Ethiopia, around 2.8 million years ago (Ma), marked by a substantial increase in C4 dietary intake among herbivores, including bovids and suids. This change was unexpectedly large and simultaneous across different species, suggesting a common environmental driver despite no evidence of rapid grassland expansion. Stable isotope analysis of tooth enamel from the Shungura Formation revealed higher δ13C values post-2.8 Ma in Tragelaphus nakuae, surpassing levels observed in living tragelaphins, and similar shifts in Kolpochoerus limnetes, challenging assumptions about dietary evolution. These findings highlight a previously underappreciated ecological transformation during the late Pliocene, raising questions about the resolution of ecological proxies and the correlation between vegetation and faunal changes.

Bibi, F., Souron, A., Bocherens, H., Uno, K., & Boisserie, J.-R. (2013). Ecological change in the lower Omo Valley around 2.8 Ma. Biology Letters, 9(1), 20120890. https://doi.org/10.1098/rsbl.2012.0890