Dietary variability of extinct tayassuids and modern white-lipped peccaries (Tayassu pecari) as inferred from dental microwear and stable isotope analysis

Abstract

Prior geochemical work documents dietary shifts coincident with climate change in extinct peccaries, with taxa typically shifting between browsing and mixed-feeding. This study employs dental microwear texture analysis (DMTA) and stable carbon isotopes to interpret the diet of extinct peccaries in Florida, specifically Platygonus, Mylohyus, and Protherohyus from the late Miocene throughout the Pleistocene, to evaluate how dietary behavior has fluctuated over time. When Mylohyus and Protherohyus coexisted in the Hemphillian, Mylohyus consumed C3 food sources with harder textures, consistent with the consumption of woody browse, while Protherohyus consumed a greater proportion of C4 vegetation (likely grass). During the Blancan, both Platygonus and Mylohyus can be considered primarily C3 browsers, based on both DMTA and stable isotope data. However, during the Irvingtonian, both Mylohyus and Platygonus consumed a larger proportion of C4 vegetation than during previous North American Land Mammal Ages (NALMAs). Platygonus consumed predominantly C3 vegetation during the Rancholabrean, while Mylohyus consumed a mixture of C3 and C4 vegetation in more open environments. Independent of NALMA, Platygonus consumed predominantly tough vegetation, (e.g., tough leaves and/or grass) while Mylohyus consumed harder food items, consistent with morphological differences in their teeth. In contrast, extant Tayassu peccaries are obligate C3 feeders and show no evidence of C4 consumption. Further, Tayassu are indistinguishable in all dental microwear textural properties from both of their extinct relatives, suggesting that while extant peccaries eat primarily foods from forested environments, those foods are highly variable in textural properties. Collectively, these data suggest that extinct peccaries, Mylohyus and Platygonus, altered their diet over time and possibly in response to changing climates.