Meeting Abstract
Jaw protrusion is one of the more remarkable functional abilities to have evolved among fishes. We sought to determine if changes in protrusion mechanics are tightly linked to divergence along one of the most important ecological axes in aquatic systems: the bentho-pelagic axis. We examined skull morphology and feeding kinematics in the damselfishes, which constitute a highly-successful radiation of marine fishes that have undergone repeated convergence on three ecological states: planktivory (pelagic feeding), a limited form of omnivory (bentho-pelagic feeding) and herbivory (benthic feeding). The ten species examined included multiple examples of convergence on all three of these feeding niches. Using phylogenetic comparative analyses of both skull shape and kinematic data we determined that: 1) planktivorous damselfishes have significant differences in jaw protrusion ability relative to members of the other trophic guilds; 2) jaw protrusion ability has evolved in correlation with a suite of additional morphological and functional traits associated with feeding; 3) pomacentrids capable of extensive protrusion exhibit higher levels of functional integration between upper and lower jaw movement than other species and 4) the best- supported evolutionary model for the diversification of damselfish feeding mechanics indicates that their repeated ecological convergence has been accompanied by morphological and kinematic convergence on three adaptive peaks. The evolution of jaw protrusion has been tightly linked to bentho-pelagic divergence in damselfishes and the evolution of their trophic morphology has involved repeated convergence in form, function and ecology.
