Researchers report shifts in the diet of fossil herbivores, indicating changes in environment. The Shungura Formation in southwestern Ethiopia contains hominin and herbivore fossils, and exploring the ecology of the taxa in this formation could uncover the environmental context of hominin evolution. Stable carbon isotope data from fossilized herbivores can provide insight into animal diets as well as diet shifts. Enquye W. Negash and colleagues analyzed more than 1,050 fossil teeth representing nine herbivore families that span the period between 3.6 million and 1.05 million years ago. The diet of herbivores shifted from a high proportion of mixed feeders before 2.9 million years ago to a high proportion of grazers between 2.7 and 1.9 million years ago and after 1.9 million years ago. Two major changes are indicated at around 2.7 million years ago and 2.0 million years ago, with the former coinciding with the first appearance of the hominin genus Paranthropus. Additionally, the shift suggests that Australopithecus, which lived prior to 2.7 million years ago, may have lived in a primarily wooded ecosystem compared to Paranthropus, which likely lived in an open environment. According to the authors, the shift in herbivore diet provides context for the contemporary shift in hominin diet, with the combined results showing how mammals respond to environmental changes.
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Article #20-06982: "Dietary trends in herbivores from the Shungura Formation, southwestern Ethiopia," by Enquye W. Negash et al.
MEDIA CONTACT: Enquye W. Negash, George Washington University, Washington, DC; e-mail: enquyen@gwu.edu
Proceedings of the National Academy of Sciences