Dietary reconstruction of the Miocene primates from Patagonia using dental microwear and isotope analyses
Patagonia, the southermost part of South America, and La Venta, in the northern Neotropics of Colombia, are the two most important regions preserving fossil primates in South America, with about one third of the record (Tejedor, 2013; Tejedor & Novo, 2018, and references therein). La Venta is characterized by the presence of anatomically more advanced taxa, closer to the living groups that are widespread across the intertropical areas. To the contrary, the Patagonian primates are a subject of an intense debate about their phylogenetic relationships, especially some key taxa: Soriacebus, Mazzonicebus, and Proteropithecia (see below), as well as Carlocebus and Dolichocebus. Currently, it appears that, with the exception of callitrichines, several platyrrhine clades were probably present in Patagonia during early and middle Miocene times, such as cebines and pitheciines (Rosenberger et al., 1990; Tejedor, 2000; Fleagle & Tejedor, 2002; Tejedor, 2005; Tejedor & Novo, 2018; but see Kay, 2015, for a different view). Having pitheciines and cebines present in Patagonia, all more primitive than the forms found in La Venta, Colombia (Hartwig & Meldrum, 2002; Tejedor & Muñoz Saba, 2013), suggests that there is an excellent opportunity to investigate how these clades originated and differentiated and extended their geographic range up to Patagonia. In other words, while the La Venta fauna is quite modern and tells us much about later phases of platyrrhine evolution, it appears that Patagonia has more potential to elucidate earlier phases in the radiation of modern clades, collecting the information from morphology, paleoecology, and paleoenvironments. In this sense, inferring the paleodiet of the primate fauna based on the general morphology of the dentition and enamel microwear, is crucial for paleoecological reconstructions, adding the data provided by stable isotopes of tooth enamel. All this information may serve to determine the paleoenvironmental context of the Patagonian platyrrhines, the resources from which they got the food, and the general background of the climate during the development of the Middle Miocene Climatic Optimum, a global event that certainly had strong evidences in the Patagonian mammals.