Morpho-functional adaptations of three species of Spongia (Porifera, Demospongiae) from a Mediterranean vertical cliff

Spongia virgultosa, S. officinalis and S. agaricina probably arise from a s ingle ancestor and at present, colonize three different habitats along the Portofino Promontory cliff and deep rocks (Ligurian Sea, Italy) from the fi rst 2-3 m to 100 m depth. S. virgultosa evolved an encrusting shape to face the high water movement of shallow coastal water, whereas the two shapes ( elephant-ear or vase) of S. agaricina are related to the interaction with t he local water movement and the consequent sediment transport. S. officinal is is more variable in shape and more euryoecious than the others.