Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information

Nicolas Bourgon (1, 2) , Klervia Jaouen (3) , Anne-Marie Bacon (4) , Klaus Peter Jochum , Elise Dufour (5) , Philippe Duringer (6) , Jean-Luc Ponche (7) , Renaud Joannes-Boyau , Quentin Boesch (6) , Pierre-Olivier Antoine (8) , Manon Hullot (8) , Ulrike Weis , Ellen Schulz-Kornas , Manuel Trost , Denis Fiorillo (5) , Fabrice Demeter (9) , Elise Patole-Edoumba , Laura Shackelford , Tyler Dunn , Alexandra Zachwieja , Somoh Duangthongchit , Thongsa Sayavonkhamdy , Phonephanh Sichanthongtip , Daovee Sihanam , Viengkeo Souksavatdy , Jean-Jacques Hublin (10) , Thomas Tütken (2)

1 Max Planck Institute for Evolutionary Anthropology [Leipzig]
2 JGU - Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University
3 GET - Géosciences Environnement Toulouse
4 BABEL - Biologie, anthropologie, biométrie, épigénétique, lignées : De la diversité des populations à l'individu, de l'identification à l'identité
5 AASPE - Archéozoologie, archéobotanique : sociétés, pratiques et environnements
6 IPGS - Institut de physique du globe de Strasbourg
7 LIVE - Laboratoire Image, Ville, Environnement
8 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
9 EA - Éco-Anthropologie
10 Collège de France - Chaire internationale Paléoanthropologie

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.

Mots clés: zinc; stable isotopes; diagenesis; trophic ecology; diet

Domaines: Paléontologie; Anthropologie biologique

Nicolas Bourgon, Klervia Jaouen, Anne-Marie Bacon, Klaus Peter Jochum, Elise Dufour, et al.. Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information. Proceedings of the National Academy of Sciences of the United States of America, 2020, 117 (9), pp.4675-4681. ⟨10.1073/pnas.1911744117⟩. ⟨hal-02978793⟩