image: Paranthropus aethiopicus mandible (the oldest specimen analyzed; Specimen L55s-33). view more
Credit: Image credit: Jonathan G. Wynn
Researchers report isotopic evidence of how hominin species responded to changes in food availability. The hominin genus Paranthropus displays a divergence in diet, with both dental microwear and stable isotope evidence suggesting that P. robustus consumed hard objects and P. boisei consumed a diet based on plants that use the C4 photosynthetic pathway. The timing of the diet divergence, however, is not clear. Jonathan G. Wynn and colleagues analyzed stable carbon isotope data from 86 hominin fossils from the Shungura and Usno Formations in Ethiopia, spanning the period between 3 million and 2 million years ago. Around 2.37 million years ago, the median carbon-13 to carbon-12 isotope ratio in the hominin teeth shifted significantly from an isotopic signature suggestive of a diet of C3 plants to a signature suggestive of a C4-plant-based diet. The shift occured after the emergence of P. aethiopicus, a sister clade to P. robustus and P. boisei, but before the emergence of P. boisei. Further, P. robustus did not experience the same isotopic shift, which could be due to differences in plant nutritional content in the regions that the respective species inhabited. The findings suggest that the shift in hominin diet coincided with an isotopic shift in other mammals and illustrate the ways hominins responded to changes in food availability, according to the authors.
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Article #20-06221: "Isotopic evidence for the timing of the dietary shift toward C4 foods in eastern African Paranthropus," by Jonathan G. Wynn et al.
MEDIA CONTACT: Jonathan G. Wynn, National Science Foundation, Alexandria, VA; e-mail: jwynn@nsf.gov
Journal
Proceedings of the National Academy of Sciences