Abstract
The late early Miocene Béon 1 locality has yielded an abundant vertebrate fauna with more than 5,000 remains assigned to four rhinocerotid species: the stem rhinocerotine Plesiaceratherium mirallesi, the teleoceratines Prosantorhinus douvillei and Brachypotherium brachypus, and the early-diverging elasmotheriine Hispanotherium beonense. Such a profusion of closely related large herbivore species co-occurring raises questions about habitat capacity and niche partitioning. To investigate potential niche partitioning of Béon 1 rhinocerotids, we studied their ecology through texture microwear (short-term diet proxy), mesowear (long-term diet proxy), and enamel hypoplasia (environmental stress proxy). The mesowear revealed no significant differences between the species, with low scores suggesting browsing preferences, while microwear suggested subtle dietary variations. We concluded that Plesiaceratherium mirallesi and Prosantorhinus douvillei were browsers probably consuming a lot of leaves, while Brachypotherium brachypus and Hispanotherium beonense were mixed-feeders. Concerning hypoplasia, the overall prevalence was high at Béon 1, with more than 25 % of the teeth affected (216 teeth out of 832). There were, however, huge discrepancies depending on the species, tooth loci, or type of hypoplasia considered. Interestingly, H. beonense had the greatest dietary flexibility and the lowest hypoplasia prevalence (13.04 %). Both teleoceratines were very affected by hypoplasia, suggesting whether a comparable high sensitivity to stress (phylogeny) or similar habitat-related stresses (environment). The most affected loci were p4 (48.15 %), m3 (46.81 %), and D4 (46.15 %), reflecting vulnerability periods around weaning, environment-related, and near birth, respectively.