Stable carbon and nitrogen isotope ratios of collagen from bone and dentin have frequently been used for dietary reconstruction, but this method is limited by protein preservation. Isotopes of the trace element zinc (Zn) in bioapatite constitute a promising proxy to infer dietary information from extant and extinct vertebrates. The 66Zn/64Zn ratio (expressed as δ66Zn value) shows an enrichment of the heavy isotope in mammals along each trophic step. However, preservation of diet-related δ66Zn values in fossil teeth has not been assessed yet. Here, we analyzed enamel of fossil teeth from the Late Pleistocene (38.4-13.5 ka) mammalian assemblage of the Tam Hay Marklot (THM) cave in northeastern Laos, to reconstruct the food web and assess the preservation of original δ66Zn values. Distinct enamel δ66Zn values of the fossil taxa (δ66Zncarnivore < δ66Znomnivore < δ66Znherbivore) according to their expected feeding habits were observed, with a trophic carnivore-herbivore spacing of +0.60% and omnivores having intermediate values. Zn and trace element concentration profiles similar to those of modern teeth also indicate minimal impact of diagenesis on the enamel. While further work is needed to explore preservation for settings with different taphonomic conditions, the diet-related δ66Zn values in fossil enamel from THM cave suggest an excellent long-term preservation potential, even under tropical conditions that are well known to be adverse for collagen preservation. Zinc isotopes could thus provide a new tool to assess the diet of fossil hominins and associated fauna, as well as trophic relationships in past food webs.
|Original language||English (US)|
|Number of pages||7|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Mar 3 2020|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. We thank K. Schilling and B. Brumme (Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig) as well as O. Tombret (UMR 7209 AASPE) for technical support; S. Steinbrenner (Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig) who performed the C and N analysis; R. Mundry (Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig) for his valuable help and insight with the LMM; R. Barr, C. Zickert, L. Därr, A. Salzer, and L. Schymanski (Multimedia Department, Max Planck Institute for Evolutionary Anthropology, Leipzig) for their help with pictures and figure presentation; Christine Lefèvre, Joséphine Lesur, and Aurélie Verguin of the UMR 7209 (AASPE), Muséum National d’Histoire Naturelle, in Paris, for the agreement and access to the mammal collection; and M. Sponheimer and P. Telouk for their helpful discussions. We would like to acknowledge the support and thank the Max Planck Society and the Deutsche Forschungsgemeinschaft (“PALÄODIET” Project 378496604) for funding this study. T.T. and K.J. received funding by the European Research Council under the European Union’s Horizon 2020 research and innovation program Grant Agreements 681450 and 803676, respectively. Funding for the excavation of the Marklot cave in 2015 was provided by the University of Strasbourg (Unistra/EOST UMR 7516) and the Unité Propre de Recherche (UPR) 2147 of CNRS Dynamique de l’évolution humaine, France, and the University of Illinois at Urbana–Champaign. Finally, we would like also to thank V.S. and S. Luangaphay of the Department of National Heritage, Ministry of Information and Culture in Vientiane, Laos, for their authorization to study the Marklot fauna.
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- Stable isotopes
- Trophic ecology