Isotopic study of lipids and collagen in bones from archaeological and modern ungulates for the study of paleodiets in Argentina

In this paper we carried out a sequential extraction of lipids and collagen and obtained carbon and nitrogen stable isotope values of archaeological and modern bone samples of native ungulates from the Argentine Patagonia (Lama guanicoe, Pudu puda, Hippocamelus bisulcus) and Northwest (Lama sp., Vicugna vicugna). Collagen and lipids are biomolecules with exceptional survival rates in archaeological bone matrixes and provide complementary information about diet. We studied 28 ungulate specimens and obtained bulk δ13C values (δ13Clip, δ13Ccoll) and δ15N values to evaluate protein diet, whole diet, and offsets between values from lipids and collagen (Δ13Clip-coll). Results showed greater variability in the offsets of the different ungulate species than previously reported for terrestrial herbivores. This variability could be attributed to differences in body mass, particular niche adaptations, seasonal metabolic stress, diet change, and/ or human-ungulate interactions in each case. This study sheds light on the potential of paired lipid-collagen stable isotope values for interpreting paleodiet dynamics and unraveling individual life histories.