Systematics and life habit in Serpula israelitica Amoureux, 1977(Polychaeta Serpulidae) from the Mediterranean with remarks onother soft-bottom serpulids

摘要

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