An updated review of the occurrence of Bathypolypus sponsalis (Cephalopoda: Octopodidae) in the Italian seas and notes on its distribution in the Mediterranean.

The occurrence and bathymetric distribution of Bathypolypus sponsalis in the Italian waters was reviewed on the basis of trawl surveys data routinely collected from 1994 to 2004 within the framework of the Italian GRUND and the International MEDITS research programs. All Italian seas were investigated covering a total area of about 290,000 km2 within the depth interval 10-800 m. Biomass and abundance indices were computed. Bathypolypus sponsalis was caught in the Ligurian Sea, in the Sardinian Sea, in the Sardinian Channel and in the Strait of Sicily, in the depth range 265-704 m. The species was never recorded in the Ionian and the Adriatic Sea and only few records are available for the Tyrrhenian Sea (some specimens caught off northwestern Sicily). Present results, along with information from the literature, indicate the core of occurrence for B. sponsalis in the Mediterranean to be located in the western basin. This study addresses the absence of this species in the above mentioned areas on the basis of biogeographical and oceanographical information, paying particular interest to the possibility that the intermediate waters circulation plays a significant part in determining the distribution of the species.