Systematics and life habit in Serpula israelitica Amoureux, 1976 (Polychaeta Serpulidae) from the Mediterranean with remarks on other soft-bottom serpulids

A redescription of the poorly known species Serpula israelitica Amoureux, 1977 from the central Mediterranean is given, using both traditional and new systematic characters. Morphological traits are compared and contrasted with other Mediterranean Serpula species to understand their interrelationships. The distribution, ecology and life history of S. israelitica are also discussed. The species belongs to a unique group of serpulids that settle not on hard substrates but on sandy to muddy bottoms from shelf to upper slope, where they exhibit a freeliving habit. Mainly empty tubes are found, most of which are detached anterior/ distal parts, occasionally closed off at their posterior/proximal damaged end by a mineralized tabula, a transverse internal tube structure ensuring protection to the animal inside its broken tube. Hypotheses on different functional adaptations to counteract sinking in other soft-bottom serpulids are given