Meeting Abstract
Bats represent the one of the largest (1300+ species) and most ecologically diverse orders of mammals, and exhibit a remarkable range of sensory and feeding specializations. Here, we explore the impacts of conflicting functional demands from both sensory and dietary functions on the evolution of skull shape within the bat radiation. We generated 3D geometric morphometric datasets of the skull of more than 200 species representing all bat families, dietary niches and types of echolocators. We used these data in a series of phylogenetic comparative analyses to uncover the macroevolutionary patterns and processes shaping skull diversity across bats. These included: (1) comparisons of an estimated adaptive landscape (with no a priori assumptions) of cranial and mandible shape evolution with transitions in diet and echolocation type across bats, (2) quantification of patterns of skull shape disparity across the evolutionary history of bats, and (3) tests of associations between shifts in skull modularity skull and ecological transitions. We found numerous adaptive shifts in skull shape evolution among bats; early shifts were associated with transitions between echolocators and non-echolocators, as well as between oral and nasal emitters, while later shifts in skull shape evolution were associated with diet within Phyllostomidae. Model fitting further supported a divergence between the major ecological pressures on cranium and mandible shape. Early shifts in echolocation seem to have strongly modulated cranial disparity and may have been associated with changes in skull modularity and lability. Conversely, shifts in skull shape may have been driven by dietary opportunities within Phyllostomidae. Together, these results demonstrate how the varying importance of different functional demands may impact the evolution of skull shape.
