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Sponheimer M, Alemseged Z, Cerling TE, Grine FE, Kimbel WH, Leakey MG, Lee-Thorp JA, Manthi FK, Reed KE, Wood BA, Wynn JG. Isotopic evidence of early hominin diets. Proc Natl Acad Sci U S A 2013; 110:10513-10518. [PMCID: PMC3696771 DOI: 10.1073/pnas.1222579110] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023] Open
Abstract
Carbon isotope studies of early hominins from southern Africa showed that their diets differed markedly from the diets of extant apes. Only recently, however, has a major influx of isotopic data from eastern Africa allowed for broad taxonomic, temporal, and regional comparisons among hominins. Before 4 Ma, hominins had diets that were dominated by C3 resources and were, in that sense, similar to extant chimpanzees. By about 3.5 Ma, multiple hominin taxa began incorporating 13C-enriched [C4 or crassulacean acid metabolism (CAM)] foods in their diets and had highly variable carbon isotope compositions which are atypical for African mammals. By about 2.5 Ma, Paranthropus in eastern Africa diverged toward C4/CAM specialization and occupied an isotopic niche unknown in catarrhine primates, except in the fossil relations of grass-eating geladas (Theropithecus gelada ). At the same time, other taxa (e.g., Australopithecus africanus ) continued to have highly mixed and varied C3/C4 diets. Overall, there is a trend toward greater consumption of 13C-enriched foods in early hominins over time, although this trend varies by region. Hominin carbon isotope ratios also increase with postcanine tooth area and mandibular cross-sectional area, which could indicate that these foods played a role in the evolution of australopith masticatory robusticity. The 13C-enriched resources that hominins ate remain unknown and must await additional integration of existing paleodietary proxy data and new research on the distribution, abundance, nutrition, and mechanical properties of C4 (and CAM) plants.
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Affiliation(s)
- Matt Sponheimer
- Department of Anthropology, University of Colorado, Boulder, CO 80309
| | - Zeresenay Alemseged
- Department of Anthropology, California Academy of Sciences, San Francisco, CA 94118
| | - Thure E. Cerling
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112
| | - Frederick E. Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794
| | - William H. Kimbel
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287
| | - Meave G. Leakey
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794
- Turkana Basin Institute, 00502 Nairobi, Kenya
| | - Julia A. Lee-Thorp
- Research Laboratory for Archaeology, Oxford University, Oxford OX1 3QY, United Kingdom
| | | | - Kaye E. Reed
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287
| | - Bernard A. Wood
- Center for the Advanced Study of Hominid Paleobiology, Department of Anthropology, George Washington University, Washington, DC 20052; and
| | - Jonathan G. Wynn
- Department of Geology, University of South Florida, Tampa, FL 33620
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Diet of Australopithecus afarensis from the Pliocene Hadar Formation, Ethiopia. Proc Natl Acad Sci U S A 2013; 110:10495-500. [PMID: 23733965 DOI: 10.1073/pnas.1222559110] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The enhanced dietary flexibility of early hominins to include consumption of C4/crassulacean acid metabolism (CAM) foods (i.e., foods derived from grasses, sedges, and succulents common in tropical savannas and deserts) likely represents a significant ecological and behavioral distinction from both extant great apes and the last common ancestor that we shared with great apes. Here, we use stable carbon isotopic data from 20 samples of Australopithecus afarensis from Hadar and Dikika, Ethiopia (>3.4-2.9 Ma) to show that this species consumed a diet with significant C4/CAM foods, differing from its putative ancestor Au. anamensis. Furthermore, there is no temporal trend in the amount of C4/CAM food consumption over the age of the samples analyzed, and the amount of C4/CAM food intake was highly variable, even within a single narrow stratigraphic interval. As such, Au. afarensis was a key participant in the C4/CAM dietary expansion by early australopiths of the middle Pliocene. The middle Pliocene expansion of the eastern African australopith diet to include savanna-based foods represents a shift to use of plant food resources that were already abundant in hominin environments for at least 1 million y and sets the stage for dietary differentiation and niche specialization by subsequent hominin taxa.
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Abstract
Theropithecus was a common large-bodied primate that co-occurred with hominins in many Plio-Pleistocene deposits in East and South Africa. Stable isotope analyses of tooth enamel from T. brumpti (4.0-2.5 Ma) and T. oswaldi (2.0-1.0 Ma) in Kenya show that the earliest Theropithecus at 4 Ma had a diet dominated by C4 resources. Progressively, this genus increased the proportion of C4-derived resources in its diet and by 1.0 Ma, had a diet that was nearly 100% C4-derived. It is likely that this diet was comprised of grasses or sedges; stable isotopes cannot, by themselves, give an indication of the relative importance of leaves, seeds, or underground storage organs to the diet of this primate. Theropithecus throughout the 4- to 1-Ma time range has a diet that is more C4-based than contemporaneous hominins of the genera Australopithecus, Kenyanthropus, and Homo; however, Theropithecus and Paranthropus have similar proportions of C4-based resources in their respective diets.
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