Morphofunctional segregation in molossid bat species (Chiroptera: Molossidae) from the South American southern cone

Abstract

Molossid bats exhibit a great diversity of size and skull morphology which likely reflects differences in diet a trophic function and may be indicative of the degree of resource partitioning and ecological overlap in the group. We explored the morphofunctional variation of the skull in molossids from Argentina, where 18 species occur, and are representative of the vast South American Southern Cone region. We measured 18 craniodental variables in 377 specimens representing all 18 species. We performed a multivariate analysis using craniodental variables, with and without correcting for body mass variation, and applied a comparative phylogenetic method to determine the importance of phylogeny in morphofunctional variation. The specimens distribution in morphospace showed a clear segregation between species on the basis of skull size and morphological differences that related with prey selection, and associated with other important factors such as echolocation and flight. Our results highlighted that the morphological pattern observed was determined principally by the evolutionary history of the family, as we identified major events of expansion of occupied morphospace with the origination of large species such as those in Eumops as well as small species of Molossops and Cynomops. Our findings suggest that the joint effects of history, size and functional morphology boosted the evolution of Neotropical molossids and facilitated the coexistence of related species.