Researchers use fossil teeth to open up dietary shifts in ancient herbivores and hominins

A new study published this week in the journal Proceedings of the National Academy of Sciences documents dietary changes in herbivores that lived between 1-3 million years ago in the Lower Omo Valley of Ethiopia. The research team, led by Enquye Negash, a postdoctoral researcher at the George Washington University Center for the Advanced Study of Human Paleobiology, examined stable isotopes in the fossil teeth of herbivores such as antelopes and pigs and found a shift away from C3-derived foods. , characteristic of woody vegetation, for C4-derived food, representative of grass and seed. The shift occurred at two distinct time periods, about 2.7 million years ago and 2 million years ago, when the environment of the Lower Omo Valley transitioned to open savannah.

The study, “Dietary Trends in Herbivores from the Shungura Formation, Southwest Ethiopia,” served as a comparative framework for an associated hominin diet study, also published this week, of which Negash was a co-author. The associated study, “Isotopic evidence for the timing of diabetes shift to C4 foods in eastern African Paranthropus,” examined carbon isotope data from the fossil tooth enamel of Paranthropus boisei, a non-anestral hominin relative.

Led by Jonathan Wynn, now a program director in the Earth Sciences division of the National Science Foundation, the research team behind that paper found a profound shift to the consumption of C4-derived food about 2.37 million years ago, which is a morphological shift of P preceded. skull and jaw of boisei. Given the direct evidence provided by the abundant, well-dated fossil teeth and their chemical composition, the new findings suggest that behavioral changes may prevent changes in apparent morphological adaptations to new foods.

“Significant dietary changes observed in our study reflect the response of herbivores to major ecological and environmental changes during this time period. This enabled us to better understand the environmental context of similar dietary changes in hominins,” says Negash.

“While we are interested in how the diets of our immediate and distant ancestors evolved to produce our modern human diet, it is very important to consider these hominins as a small part of an ecosystem that includes other plant and animal species.” t respond to changing environments in an interconnected way, “Wynn adds.