New findings of Nudipleura (Mollusca: Gastropoda) along the central-eastern coast of Sicily (Ionian Sea)

The present short note reports the finding of five Nudipleura species: one (Taringa cf. telopia) new for the Mediterranean, two (Doto maculata and Okenia longiductis) new for Sicily, one (Berthella stellata) new for the central-eastern coast of Sicily and, finally, a new record of Taringa tritorquis for the same area. For each species, information on date and site of finding, external morphology, taxonomic history, previous reports and remarks, are discussed. The finding of these species could depend on two different reasons: 1) the examined areas are transit zones for several ships which could transport the veligers or/and juvenile stages through fouling or ballast water; 2) since in these areas the marine Heterobranchia fauna has been poorly studied, many of the found species could have been overlooked until now. This work highlights the importance of a continuous monitoring to expand and deepen the knowledge of marine Heterobranchia fauna

Observations on the ghost fishing in two species of marine heterobranchs (Mollusca Gastropoda): Aplysia depilans Gmelin, 1791 (Aplysidae) and Umbraculum umbraculum ([Lightfoot], 1786) (Umbraculidae)

The present note reports for the first time the finding of two species of marine Heterobranchia within a ghost net. The stretch of the net was repeatedly wrapped in itself and formed a large tangle of spherical shape. This created several "layers" of meshes wrapped in each other, where the following species of marine heterobranchs were found: Aplysia depilans and Umbraculum umbraculum. In particular, of the former, an alive specimen was found tied to the wire of the net, and a dead specimen floating within the ghost net. Of the second species, only the shell was found

Assessment of grazing impact on deep canopy-forming species in the western Ionian Sea, Central Mediterranean

Marine forests are experiencing a severe decline in many Mediterranean areas. One of the major causes of the loss of the canopy-forming species is the overgrazing by herbivorous fishes. In the present study, the status of Treptacantha ballesterosii and Carpodesmia zosteroides populations was checked in two areas located along the central-eastern sector of Sicily. In addition, impact of herbivorous fishes, native or alien, on canopy-forming species was realized during monitoring of fish communities. It was observed that T. ballesterosii and C. zosteroides populations are in regression, particularly T. ballesterosii. Probably, the growth of this latter species may be limited by a strong herbivores' pressure. During the monitoring period, the highest number of fish species has been observed at the depths where there are T. ballesterosii thalli. Moreover, an expansion of Sparisoma cretense populations has been observed that seems to be more competitive than the other herbivorous fish Sarpa salpa. Furthermore, the parrotfish has been observed several times in the bathymetric range where there is T. ballesterosii. Therefore, it may be hypothesized that in these areas the herbivorous fish which mostly hinder the development and growth of T. ballesterosii is S. cretense

Population dynamics of Ericaria zosteroides (Ochrophyta, Fucales) in the central Mediterranean

Ericaria zosteroides is a canopy-forming macroalga belonging to the order Fucales, which dominates Mediterranean deep-water stands. In the present research, populations of E. zosteroides from three locations (Santa Maria La Scala, Scalo Pennisi and Acque Fredde) along the central-eastern coast of Sicily (Italy, central Mediterranean) were monitored for five years (from 2017 to 2021). E. zosteroides from all locations in this area share a common phenology: recruits start to appear between January-February; then during spring the frond grows and becomes fertile; in summer it begins to thin out until the autumn when almost all branches have been lost; and finally at the beginning of winter, new primary branches start to grow from the tophules. Nonetheless, we detected a difference in the most frequent size class among the studied populations, being 9 cm at Santa Maria La Scala, 6 cm at Scalo Pennisi and 4 cm at Acque Fredde. This difference could be due to the current regime, related to the tidal currents of the Strait of Messina and upwelling currents of the Ionian Sea, and the coastal morphology which determines local variations in this regime, with multiple eddies characterised by marked directional instability. The low growth rate and dynamics of these stands make them very susceptible to recovery from anthropogenic impacts. Considering that E. zosteroides is a threatened species according to the Barcelona Convention, it would be crucial to ameliorate the conservation status of the investigated populations, which currently do not present any level of protection, in order to promote their future viability

No longer so common: findings of <em>Calliopaea bellula</em> d’Orbigny 1837 (Gastropoda: Sacoglossa) and <em>Tayuva lilacina</em> (A. Gould 1852) (Gastropoda: Nudibranchia) along the central-eastern coast of Sicily (Ionian Sea)

The present note documents the finding of two species of marine heterobranch seaslugs along the central-eastern coast of Sicily (Italy, central Mediterranean): the sacoglossan Calliopaea bellula and the nudibranch Tayuva lilacina. These two species show a wide geographical range (C. bellula is present from Norway to the Black Sea, while T. lilacina is a cosmopolitan species) and in the literature were considered common species. However, in the last years, the number of findings of these species is decreasing, at least in the Western Ionian Sea, an area where these species seem to be currently rare. As documented for other Mediterranean areas, the reason for this decline in the number of marine heterobranch species might be attributable to a change in the current regime or to an increase in anthropogenic impacts around the coastal areas

New observations on two umbraculid molluscs: Tylodina perversa (Umbraculida: Tylodinidae) and Umbraculum umbraculum (Umbraculida, Umbraculidae) along the central&amp;#8209;eastern coast of Sicily

The present note aims to provide detailed information on the biology and ecology of two marine heterobranch species belonging to the order Umbraculida: Umbraculum umbraculum and Tylodina perversa. The observations were carried out through scuba dives from 2017 to May 2022 in 5 sites located along the central-eastern coast of Sicily. For each species, information on the morphology, abundance, bathymetric range, substrates and habitats, seasonality, and further remarks were here provided. Through this research, it was noted that along the central-eastern coast of Sicily, T. perversa has never been found on sponges of the genus Aplysina, its prey so far documented, but always on algal substrates. Regarding U. umbraculum, it was observed that it counts among the sponges of its diet also the poriferan C. crambe. Moreover, through this study, it was documented for the first time the breeding activity of U. umbraculum, never reported in detail

The Fucales (Ochrophyta, Phaeophyceae) of the Island of Pantelleria (Sicily Channel, Mediterranean Sea): a new contribution

In the past, only a few studies were carried out on the marine vegetation of the Island of Pantelleria, reporting a high level of biodiversity in this island. However, the most recent study, performed about 20 years ago, documented a total loss of Fucales below ca. 12 m of depth and their substitution with morphologically simpler species. In the present study, the current presence and distribution of Cystoseira s.l. and Sargassum around the Island of Pantelleria were assessed, comparing the current data with the previous studies on the marine vegetation of this island. Through monitoring activities (both snorkelling and scuba diving), 19 taxa were recorded: seven belonging to Cystoseira, six to Ericaria, four to Gongolaria, and two to Sargassum. Comparing these data with the previous studies, it was highlighted that most of the species previously reported are still present on the island. Moreover, approximately 20 years after their documented disappearance, deep-water species such as C. foeniculacea f. latiramosa, G. elegans, G. montagnei, G. montagnei v. compressa and Sargassum cf. acinarium were recorded during this study, suggesting a natural recovery for these Fucales. We recommend that, in order to guarantee a long-term conservation of these fucalean populations, it would be useful to establish a marine protected area in the Island of Pantelleria

New records of rare species in the Mediterranean Sea (May 2020)

This Collective Article presents information about 17 taxa belonging to four Phyla (one Cnidaria, two Arthropoda, four Mollusca, and ten Chordata) and extending from the Western Mediterranean to the Levantine Sea. The new records were reported from nine countries as follows: Algeria: first published records of the clingfishes Apletodon dentatus and Lepadogaster lepadogaster after 1955; France: first record of the tripletail Lobotes surinamensis in French Mediterranean waters; Italy: new records of the rare bonito Orcynopsis unicolor and the recently described nudibranch Elysia rubeni from Sicily; first records of the parasitic cirriped Sacculina eriphiae and the nudibranch Dondice trainitoi in the Ionian Sea; first record of the nudibranch Taringa tritorquis in the Mediterranean Sea; first record of the tripletail Lobotes surinamensis in the North Ionian Sea; first documented record of the cephalopod Macrotritopus defilippi in the Adriatic Sea; Slovenia: first record of the Mediterranean endemic cryptobenthic goby Odondebuenia balearica; Montenegro: several recent occurrences of the critically endangered bull ray Aetomylaeus bovinus in the South-eastern Adriatic Sea; Greece: records of the nudibranch Dondice trainitoi in the Eastern Mediterranean Sea; new record of the occurrence of the Mediterranean spearfish Tetrapturus belone from Greece (Rhodes Island); Turkey: recent captures of the vulnerable ocean sunfish Mola mola, caught by purse-seine, in the Aegean Sea and the Dardanelles; new record of the luvar Luvarus imperialis along the Aegean coast of Turkey; Cyprus: first record of the habitat-forming hydroid Lytocarpia myriophyllum, often in considerable densities; first confirmed record of the agujon needlefish Tylosurus imperialis; Syria: first record of the decapod Ethusa mascarone

“New Alien Mediterranean Biodiversity Records” (November 2021)

This Collective Article includes records of 29 alien and cryptogenic species in the Mediterranean Sea, belonging to eight Phyla (Rhodophyta, Ochrophyta, Cnidaria, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata) and coming from 11 countries. Notes published here can be divided into three different categories: occupancy estimation for wide areas, new records for the Mediterranean Sea, and new records of species expanding within the Mediterranean Sea. The first category includes a visual survey held along the coastline of Peloponnese (Greece), which yielded records of 15 species. The second category includes the first Mediterranean records of the Coho salmon Oncorhynchus kisutch (Greece) and of the Arabian monocle bream Scolopsis ghanam (Tunisia). The third category includes new records for countries (Ganonema farinosum in Malta, Cassiopea andromeda in Libya, Cingulina isseli in Greece, Okenia picoensis in Italy, Callinectes sapidus in Slovenia, Charybdis cf. hellerii in Malta, Urocaridella pulchella in Cyprus, Ablennes hians and Aluterus monoceros in Lebanon, and Fistularia petimba in Greece and Lebanon), new records for MSFD areas or regional seas (Septifer cumingii in the Greek Ionian Sea and F. petimba in the Marmara Sea), and confirmation of old, doubtful, or spurious records/statements (Branchiomma luctuosum in Tunisia, Thalamita poissonii in the Saronikos Gulf, and Pterois miles in Albania). Noteworthy, the three new records of F. petimba suggest that it may soon spread further in the Mediterranean Sea, as already happened for its congeneric Fistularia commersonii. Distributional data reported here will help tracing colonization routes of alien species in the basin and may facilitate the development of mitigation measures

New Alien Mediterranean Biodiversity Records (August 2022)

In this Collective Article on alien and cryptogenic diversity in the Mediterranean Sea we report a total of 19 species belonging to nine Phyla and coming from nine countries. Several of these records concern fish species, and of particular interest are the first records of: Terapon puta for Italian waters; Pteragopus trispilus from Malta; Plotosus lineatus from Cyprus; and the northernmost Mediterranean record of Lagocephalus sceleratus. The northernmost Mediterranean record was also reported for the sea urchin Diadema setosum. The portunid crab Thalamita poissonii was recorded for the first time in Libya. The copepod Pseudodiaptomus marinus was recorded for the first time in the Marmara Sea. The polychaete Branchiomma luctuosum was recorded for the first time from the Mediterranean coast of France. The alien anemone Diadumene lineata was recorded for the first time from Slovenia. The macroalgae Sargassum furcatum was recorded for the first time from Italy. The new Mediterranean records here reported help tracing abundance and distribution of alien and cryptic species in the Mediterranean Sea