Marine-freshwater transitions are associated with the evolution of dietary diversification in terapontid grunters (Teleostei: Terapontidae)

The ecological opportunities associated with transitions across the marine-freshwater interface are regarded as an important catalyst of diversification in a range of aquatic taxa. Here, we examined the role of these major habitat transitions and trophic diversification in a radiation of Australasian fishes using a new molecular phylogeny incorporating 37 Terapontidae species. A combined mitochondrial and nuclear gene analysis yielded a well supported tree with most nodes resolved. Ancestral terapontids appear to have been euryhaline in habitat affiliation, with a single transition to freshwater environments producing all Australasian freshwater species. Mapping of terapontid feeding modes onto the molecular phylogeny predicted carnivorous dietary habits were displayed by ancestral terapontids, which subsequently diversified into a range of additional carnivorous, omnivorous, herbivorous and detritivorous dietary modes upon transition to freshwater habitats. Comparative analyses suggest...