Diversification of feeding structures in three adult Antarctic nototheniid fish

During their evolution and speciation in the Antarctic waters, notothenioid fish occupied a variety of habitats and ecological niches. The diversification led to important variations in several morphological features related to particular aspects of their ecologies. We investigated the feeding structures and biomechanics of three phylogenetically related species (family Nototheniidae) with different ecologies: the bentho-pelagic Antarctic toothfish Dissostichus mawsoni, the pelagic Antarctic silverfish Pleuragramma antarctica, and the benthic emerald rockcod Trematomus bernacchii. The suction index (SI), the mechanical advantage in jaw closing (MA), and 14 morphological traits related to their feeding activity were analyzed. Significant differences among the species were found for all the parameters considered, supporting a high level of specialization.