Peptide Mass Fingerprinting of South American Xenarthrans: A New Resource for Zooarcheology and Palaeontology.

Xenarthrans─armadillos, anteaters, and sloths─are endemic to the Americas, primarily inhabiting the Neotropics, where they represent a key component of faunal diversity. They have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Despite their frequent occurrence in archeological and paleontological contexts, their identification is often hindered by the highly fragmented and morphologically indistinct nature of bone remains. This limits our ability to track their biogeographic histories, population dynamics, and interactions with past human populations. To address this, we present a novel set of Zooarcheology by Mass Spectrometry (ZooMS) peptide markers for ten extant and extinct Xenarthran species, enabling taxonomic identification of fragmented and morphologically indistinct bone assemblages. By enhancing the taxonomic resolution of fragmented faunal material, this work advances the reconstruction of past species distributions, long-term biodiversity trends, and human-animal interactions. Furthermore, it provides a foundation for an improved understanding of Xenarthran extinction and adaptation dynamics and can support conservation and ecosystem restoration efforts by informing models of historical biogeography and species abundance.