Stable Sr isotopes of fossil dental enamel reflect diet and digestive system differences among sympatric herbivores

Identifier:  imarina:9465149

Handle: https://hdl.handle.net/20.500.11797/imarina9465149

Authors:  Armaroli, E; Cheheb, RC; Cipriani, A; Bernardini, S; van der Made, J; Cáceres, I; Sahnouni, M; Lugli, F

Abstract:
Reconstructing the trophic (paleo)ecology and associated physiological traits of both extinct and extant taxa is essential for understanding the functioning of (past) ecosystems. In this context, novel metal stable isotope proxies offer promising tools for investigating ancient diets and, to some extent, the digestive adaptations of animals. In this study, we analyzed the stable strontium isotope composition (delta Sr-88), alongside delta C-13, delta O-18, and Sr-87/Sr-86 ratios, in fossil dental remains of herbivorous mammals from the Early Pleistocene site of Tighennif, Algeria (similar to 1.2-1.0 Ma). Traditional carbon and oxygen isotope data indicate an environment dominated by C-3 vegetation, while the Sr-87/Sr-86 ratios suggest either a relatively homogeneous strontium baseline or limited geographic mobility of the animals. Our results demonstrate that delta Sr-88 is sensitive to diagenetic alteration, with enamel samples retaining biogenic signatures comparable to those of modern mammals, whereas dentine exhibits delta Sr-88 values shifted toward positive geogenic end-members. delta Sr-88 patterns may reflect trophic niche differentiation among herbivores and potentially indicate distinct digestive physiologies, offering a novel alternative proxy for dietary and ecological reconstructions in the fossil record.