Stable isotopes in fossil hominin tooth enamel suggest a fundamental dietary shift in the Pliocene.

Research Laboratory for Archaeology, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK.
Philosophical Transactions of The Royal Society B Biological Sciences (Impact Factor: 6.31). 10/2010; 365(1556):3389-96. DOI: 10.1098/rstb.2010.0059
Source: PubMed

ABSTRACT Accumulating isotopic evidence from fossil hominin tooth enamel has provided unexpected insights into early hominin dietary ecology. Among the South African australopiths, these data demonstrate significant contributions to the diet of carbon originally fixed by C(4) photosynthesis, consisting of C(4) tropical/savannah grasses and certain sedges, and/or animals eating C(4) foods. Moreover, high-resolution analysis of tooth enamel reveals strong intra-tooth variability in many cases, suggesting seasonal-scale dietary shifts. This pattern is quite unlike that seen in any great apes, even 'savannah' chimpanzees. The overall proportions of C(4) input persisted for well over a million years, even while environments shifted from relatively closed (ca 3 Ma) to open conditions after ca 1.8 Ma. Data from East Africa suggest a more extreme scenario, where results for Paranthropus boisei indicate a diet dominated (approx. 80%) by C(4) plants, in spite of indications from their powerful 'nutcracker' morphology for diets of hard objects. We argue that such evidence for engagement with C(4) food resources may mark a fundamental transition in the evolution of hominin lineages, and that the pattern had antecedents prior to the emergence of Australopithecus africanus. Since new isotopic evidence from Aramis suggests that it was not present in Ardipithecus ramidus at 4.4 Ma, we suggest that the origins lie in the period between 3 and 4 Myr ago.

Download full-text


Available from: Matt Sponheimer, Jun 20, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dietary ecology of early hominins, particularly East and South African Paranthropus, remains poorly understood. Here I argue that an integrative approach that combines current knowledge on isotope composition, microwear textures, dental morphology and comparative studies on the extant baboon Papio cynocephalus has the potential to shed light on the possible diet(s) of Paranthropus boisei and P. robustus. Baboons eat a variety of C 4 foods, which differ considerably in nutritional value and material properties. East and South African paranthropines apparently spent longer periods of time feeding on similar C 4 foods; their morphology suggests that they exploited opposite ends of the C 4 plant food niche spectrum that is utilised by baboons. Paranthropus boisei consumed predominantly hard brittle foods, while P. robustus fed on hard tough resources. Because of the high nutrional value of some C 4 foods, a shift in dietary preferences from C 3 to C 4 sources need not have been accompanied by an extension of total feeding time. To what extent differences in food selection and time spent feeding on C 4 foods between P. boisei and P. robustus were due to habitat differences between East and South Africa, or constitute true species preferences, needs to be investigated further.
    Trends in Biological Anthropology, First edited by Karina Gerdau-Radonić, Kathleen McSweeney, 04/2015: chapter 1: pages 1-10; Oxbow., ISBN: 9781782978367
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent biomechanical analyses examining the feeding adaptations of early hominins have yielded results consistent with the hypothesis that hard foods exerted a selection pressure that influenced the evolution of australopith morphology. However, this hypothesis appears inconsistent with recent reconstructions of early hominin diet based on dental microwear and stable isotopes. Thus, it is likely that either the diets of some australopiths included a high proportion of foods these taxa were poorly adapted to consume (i.e., foods that they would not have processed efficiently), or that aspects of what we thought we knew about the functional morphology of teeth must be wrong. Evaluation of these possibilities requires a recognition that analyses based on microwear, isotopes, finite element modeling, and enamel chips and cracks each test different types of hypotheses and allow different types of inferences. Microwear and isotopic analyses are best suited to reconstructing broad dietary patterns, but are limited in their ability to falsify specific hypotheses about morphological adaptation. Conversely, finite element analysis is a tool for evaluating the mechanical basis of form-function relationships, but says little about the frequency with which specific behaviors were performed or the particular types of food that were consumed. Enamel chip and crack analyses are means of both reconstructing diet and examining biomechanics. We suggest that current evidence is consistent with the hypothesis that certain derived australopith traits are adaptations for consuming hard foods, but that australopiths had generalized diets that could include high proportions of foods that were both compliant and tough. Am J Phys Anthropol 151:339-355, 2013.© 2013 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 07/2013; 151(3):339-55. DOI:10.1002/ajpa.22285 · 2.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fallback foods (FBFs) are hypothesized to shape the ecology, morphology, and behavior of primates, including hominins. Identifying FBFs is therefore critical for revealing past and present foraging adaptations. Recent research suggests invertebrates act as seasonal FBFs for many primate species and human populations. Yet, studies measuring the consumption of invertebrates relative to ecological variation are widely lacking. We address this gap by examining food abundance and entomophagy by primates in a seasonal forest. We study foraging behavior of white-faced capuchins (Cebus capucinus)-a species renowned for its intelligence and propensity for extractive foraging-along with the abundance of invertebrates, dietary ripe fruits, pith, and bromeliads. Consumption events and processing time are recorded during focal animal samples. We determine abundance of vegetative foods through phenological and density records. Invertebrates are collected in malaise, pan, and terrestrial traps; caterpillar abundance is inferred from frass traps. Invertebrates are abundant throughout the year and capuchins consume invertebrates-including caterpillars-frequently when fruit is abundant. However, capuchins spend significantly more time processing protected invertebrates when fruit and caterpillars are low in abundance. Invertebrate foraging patterns are not uniform. Caterpillar consumption is consistent with a preferred strategy, whereas capuchins appear to fallback on invertebrates requiring high handling time. Capuchins are convergent with hominins in possessing large brains and high levels of sensorimotor intelligence, thus our research has broad implications for primate evolution, including factors shaping cognitive innovations, brain size, and the role of entomophagy in the human diet. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 05/2015; DOI:10.1002/ajpa.22767 · 2.51 Impact Factor