Deep-water scalpellomorph/coral symbiosis (Cirripedia, Pedunculata/ Hexacorallia, Scleractinia) in the North Atlantic

The heavily armored peduncles of four species of deep-water calanticid scalpellomorphs, from three distant localities across the North Atlantic, are partially overgrown by the branching scleractinian corals on which they had settled. We infer the association and overgrowths benefit the barnacles in isolating them from competitors and predators. These barnacles and their hosts represent relatively old groups (early Mesozoic and Paleogene, respectively) and therefore the relationship could have been established during their early radiation. Because the corals are capable of at least partially if not completely entombing the scaly remains of the peduncles when the barnacles die, recognizable traces of this symbiotic relationship are probably present in the fossil record.