Boring sponges (Clionidae) and their trace fossils from the coast near Rovinj (Yugoslavia)

Abstract

Boring sponges of the genus Cliona were sampled by SCUBA-diving in the Adriatic Sea near Rovinj, Yugoslavia. Boulders of limestone and shells of molluscs, infested by clionids were collected. The sponges were identified and polyester casts were made of their bore-holes. A description is presented of the spiculae of the sponges as well as their bore-holes. It appears that sponges with different spiculae excavate different borings. The borings in limestone are larger than those in shells.