Dietary and body-mass reconstruction of the Miocene neotropical batNotonycteris magdalenensis(Phyllostomidae) from La Venta, Colombia

Abstract

AbstractWith 14 species recorded, the Miocene La Venta bat fauna is the most diverse bat paleocommunity in South America. It includes the oldest plant-visiting bat in the New World and some of the earliest representatives of the extant families Phyllostomidae, Thyropteridae, and Noctilionidae. La Venta'sNotonycteris magdalenensisis an extinct member of the subfamily Phyllostominae, a group of modern Neotropical animalivorous bats, and is commonly included in studies of the evolution of Neotropical bats, but aspects of its biology remain unclear. In this study, we used multivariate dental topography analysis (DTA) to reconstruct the diet ofN. magdalenensisby quantitatively comparing measures of molar complexity with those of 25 modern noctilionoid species representing all major dietary habits in bats. We found clear differences in molar complexity between dietary guilds, indicating that DTA is potentially an informative tool to study bat ecomorphology. Our results suggestN. magdalenensiswas probably an omnivore or insectivore, rather than a carnivore like its modern relativesChrotopterus auritusandVampyrum spectrum. Also, we reconstructed the body mass ofN. magdalenensisto be ~95 g, larger than most insectivorous bats, but smaller than the largest carnivorous bat (V. spectrum). Our results confirm thatN. magdalenensiswas not a specialized carnivore. It remains to be demonstrated that the specialized carnivory ecological niche was occupied by the same lineage of phyllostomines from at least the middle Miocene. Combining our diet and body-mass reconstructions, we suggest thatN. magdalenensisexhibits morphological pre-adaptations crucial for the evolution of specialized carnivory.