Adriatic ‘opisthobranchs’ (Gastropoda, Heterobranchia): shedding light on biodiversity issues

Abstract

We herein review the Adriatic opisthobranch fauna, provide an updated checklist of 223 species and assess their distribution at regional and country levels. New Adriatic records are provided for 67 opisthobranch taxa, adding three new records for the Italian coastline, five new records for Albania, eight for Croatia and 15 for Montenegro. The presence of Hermaea bifida (Montagu, 1815), Hermaea variopicta (Costa A., 1869) and Facelina annulicornis (Chamisso & Eysenhardt, 1821) is reported for the first time from anywhere in the Adriatic Sea. Including the new findings, our inventory includes 28 species from Albania, 163 from Croatia, 178 from the Italian coastline of the Adriatic, 41 from Montenegro and 74 from Slovenia. No records were available from Bosnia and Hercegovina. Ninety species (40.4%) are widespread, and were recorded from all three main divisions (Northern, Western and Eastern Adriatic), whilst 79 species (35.4%) were reported from only one of them. At sub‐division levels, the Albanian inventory is the most dissimilar to the other country/regional lists, presumably because of the lack of targeted field surveys. The highest similarity is observed amongst the Western Adriatic, Croatia and the Italian Ionian coastline. Seven alien, one possible alien and three cryptogenic opisthobranchs were reliably recorded from the Adriatic Sea. The first Mediterranean records of five species were in the Adriatic Sea, of which four species have not been found elsewhere in the Mediterranean. Shipping and aquaculture are the probable pathways for most of the alien species. A steady rate of one to two alien introductions per decade since the 1970s was evident. The Northern Adriatic coasts are the most affected by alien invasions, probably due to repeated local introductions along with shellfish transfers (oysters, mussels, Manila clams), and heavy maritime transport.

V. Gerovasileiou et al.: New Mediterranean Biodiversity Records (July, 2017)

“…In the Mediterranean Sea it is considered an occasional sea slug recorded until now from the coast of Israel (Barchana, 2008) and the waters surrounding Italy, the Tyrrhenian Sea (Cattaneo-Vietti & Chemello, 1987) and the Mar Piccolo, Taranto-Ionian Sea (Kapiris et al, 2014). The species was not reported in the latest survey of opisthobranch mollusks in the Adriatic Sea (Zenetos et al, 2016b). Thus, our finding could be considered as the first record for the area.…”

“…No material of this species was preserved. The species was already known from all the other Adriatic countries, having been reported so far from Italy, Slovenia, Croatia and Montenegro (review in Zenetos et al, 2016b).…”

New Mediterranean Biodiversity Records (November, 2016)

“…Its distribution spans from the north-western coasts of Europe and the Macaronesian Islands in the Atlantic Ocean to the Mediterranean Sea (Ballesteros et al, 2012(Ballesteros et al, -2016. Most Mediterranean records of this species are from the north-western basin as well as from the Adriatic Sea (Ballesteros et al, 2012(Ballesteros et al, -2016Zenetos et al, 2016). It has been reported only three times from the south-eastern sectors of the eastern Mediterranean, along the Turkish coasts in the Levantine Sea (Yokeş, 2009) and the coasts of Kriti in Greece (Crocetta et al, 2015b).…”

Presence of the alien species Godiva quadricolor (Barnard, 1927) (Gastropoda Nudibranchia Facelinidae) along the coast of eastern Sicily

“…During the last century this species has been found in different tropical and temperate waters of the world: Mozambique (Macnae, 1954), Tanzania (Willan, 2004), Ghana (Edmunds, 1977), Australia (Willan, 1987), Morocco (Atlantic Ocean) and the Strait of Gibraltar (Cervera et al, 2010). In the Mediterranean Sea, apart from the Strait of Gibraltar (Bay of Algeciras), this nudibranch has been reported also along the coasts of France (Étang de Thau) (Crocetta & Malegue in Gerovasileiou et al, 2017) and in several coasts of Italy: in the Fusaro lake in the Gulf of Naples (Cattaneo-Vietti et al, 1990), in the Sabaudia lake near Latina (Macali et al, 2013), at Noli in the Ligurian Sea (Betti et al, 2015), in the North Adriatic, among the coasts of Ravenna (Zenetos et al, 2016), and in the Faro lake in Sicily (Furfaro et al, 2018). In the coasts of Noli and Ravenna this species appeared only temporary (Betti et al, 2015;Zenetos et al, 2016), while in the lakes of Fusaro and Faro G. quadricolor still forms stable populations (Villani & Martinez, 1993;Furfaro et al, 2018).…”