Meeting Abstract
Triggerfishes and filefishes (superfamily Balistoidea) exhibit a wide range of morphological diversity including median fins that lie on a continuum from high to low aspect ratio. High aspect ratio median fins are associated with increased balistoid endurance swimming performance, while low aspect ratio fins likely facilitate short bursts of speed. We predicted that links between morphology and swimming performance could explain patterns of balistoid fishes convergently colonizing marine habitats from coral reefs to the open ocean and evolving planktivorous, grazing and predatory feeding modes. We hypothesized that balistoid species with high aspect ratio fins are associated with open water habitats and planktivory, ecologies requiring endurance swimming. Conversely, we predicted that fishes with low aspect ratio fins are associated with reefs and benthic grazing, ecologies requiring quick bursts of speed. To test these hypotheses, we calculated fin aspect ratios and conducted geometric morphometric analyses of fin and body shapes of 450 individuals representing 80 balistoid species and classified each species by primary habitat use and feeding mode. Ancestral state reconstructions revealed multiple convergence events on both high and low aspect ratio fins. We discovered multiple ecomorphology relationships such as reef-associated filefishes converging on deep bodies and low aspect ratio fins (Wheatsheaf index = 1.79, P = 0.023). The use of swimming performance to inform the interpretation of our ecomorphology results demonstrates the importance of combining functional and ecological research to thoroughly explore how and why species evolve novel morphologies and ecologies. Funded by NSF GRFP 1144082 and 1746045, IOS 1425049 and DEB 1541547.
