Rol relativo de la dieta y el tamaño del encéfalo en la diversificación del paladar de murciélagos frugívoros (Phyllostomidae: Stenodermatinae)

Abstract

Dietary diversity and morphological integration of the rostral and caudal modules of the skull can explain the morphological diversity of the rostrum in phyllostomids, the largest neotropical radiation of bats. However, these relationships have been assessed at the family level, and the patterns at lower macroevolutionary scales —e. g., within the different adaptive zones where these bats diversified— remain unknown. Here we examined the evolutionary relationships between trophic position and brain volume —as a proxy for the size of the neurocranium— with regard to palate morphology in 43 species of specialized frugivores of the subfamily Stenodermatinae. We used phylogenetic lineal models and accounted for phylogenetic uncertainty. Trophic position was not evolutionarily related to palate morphology. In contrast, as brain size increased, palate size increased as well, and palates became relatively wider. These results demonstrate that the tight relationship between the two modules of the skull are consistent at different macroevolutionary scales. But this pattern may vary between species that diversified in other adaptive optima —e. g., nectarivory or sanguivory— because different types of peramorphosis explain the development of the skull in species with different trophic specializations. Our results also suggest that not only wider palates but thicker masticatory muscles coevolved with larger brains. The trade-offs that probably occurred during the diversification of these structures, considering the limitations of flight, remain to be tested. This dissertation provides new insights into the macroevolutionary dynamics of the largest group of neotropical frugivorous bats.