Meeting Abstract

8.3  Saturday, Jan. 4 08:16  Singing through the nose: cranial modularity in nasal-emitting bats SANTANA, SE; University of Washington ssantana@uw.edu

Changes in cranial modularity can evolve rapidly in response to selection, but mammals seem to have maintained a consistent pattern of cranial integration throughout their evolutionary history and across remarkable morphological and ecological diversity. Mammal skulls are composed by a rostral and braincase modules, and their evolution can be related to their primary roles in feeding, housing sensory organs and encasing the brain. However, a few lineages have evolved novel, fitness-relevant, cranial functions that could have resulted in evolutionary changes to this two-module scheme. I investigate if one of these functions, echolocation through nasal emission, is associated with a derived pattern of cranial modularity in a diverse lineage of bats (Rhinolophidae). I use phylogenetic, geometric morphometric and comparative analyses test if a third cranial module, the “nasal dome”, has evolved in rhinolophids. I also examine trends in skull shape evolution across the wide geographic range occupied by rhinolophids. The results of this study indicate that, despite broad variation in the shape of the nasal dome, the integration of the rhinolophid skull is still highly consistent with conserved patterns of mammalian modularity. Across their geographic distribution, cranial shape in rhinolophids follows disparate trends in African versus South Asian species, which could reflect specializations to dietary and environmental factors. The results of this study highlight the potential of a relatively simple modular template for generating broad morphological and functional diversity in mammals.