Turbo radiatus Gmelin, 1791

Orfanidis, Sotiris, Alvito, Andrea, Azzurro, Ernesto, Badreddine, Ali, Souissi, Jamila Ben, Chamorro, Manuel, Crocetta, Fabio, Dalyan, Cem, Fortič, Ana, Galanti, Luca, Geyran, Kemal, Ghanem, Raouia, Goruppi, Alenka, Grech, Daniele, Katsanevakis, Stelios, Madrenas, Enric, Mastrototaro, Fransesco, Montesanto, Federica, Pavičić, Mišo, Pica, Daniela, Pola, Lisa, Pontes, Miquel, Ragkousis, Michail, Rosso, Antonietta, Sánchez-Tocino, Luis, Figueroa, J. Manuel Tierno De, Tiralongo, Francesco, Tirelli, Valentina, Tsioli, Soultana, Tunçer, Sezginer, Vrdoljak, Dario, Vuletin, Verdan, Zaouali, Jeanne & Zenetos, Argyro, 2021, New Alien Mediterranean Biodiversity Records (March 2021), Mediterranean Marine Science 22 (1), pp. 180-198 : 184-185

3.1 Turbo radiatus Gmelin, 1791 (Mollusca: Gastropoda) entered the Mediterranean Sea: a first record from Lebanon

Ali BADREDDINE and Fabio CROCETTA

The rayed dwarf-turban Turbo radiatus Gmelin, 1791 is a mollusc of the family Turbinidae Rafinesque, 1815 characterized by a medium-sized (up to about 75 mm, approximately equal in height and width), heavy, and solid shell, with a relatively tall spire and a large inflated body whorl. Strong spiral cords encircle all whorls, although those on the shoulder and the periphery of the body whorl may have sharper lamellate folds, and the outer lip is imbricate. The suture is deep, and the umbilicus is closed. The aperture is round. The shell colour ranges from grey/ ivory/beige to brown with a mottled pattern, and the aperture is whitish/yellowish. The operculum is thick and usually white/grey, but mostly is smooth, a character that allow its easy distinction from the very similar congeneric species Turbo argyrostomus Linnaeus, 1758 (Bosch & Bosch, 1989; Alf & Kreipl, 2003). Turbo radiatus is widespread in the Indo-Pacific region, including the Red Sea and the Persian Gulf, where it lives on reefs in shallow waters (Alf & Kreipl, 2003; Heiman et al., 2012).

During fieldwork carried out on the 31 th December 2020, an unknown turbinid species was first observed in the tide pools of the vermetid reef of Saksakiyeh (33.4396° N, 35.2741° E), southern Lebanon ( Fig. 4A ). After a careful inspection of the area, more than 20 individuals were observed, three of which were sampled for further identification (total height ~ 4.1-5.3 cm) ( Fig. 4B ). They were subsequently ascribed to T. radiatus based on the morphological characters listed above, and preserved in the private collection of the first author (AB). To the best of our knowledge, such a finding constitutes the first record of this species not only in Lebanon, but in the Mediterranean Sea as a whole (Zenetos & Galanidi, 2020; Crocetta et al., 2020) .

No certainties occur regarding the pathway of arrival of T. radiatus in Lebanon and in the Mediterranean Sea. However, taking into account that the species is widespread in the Red Sea and that Lebanon lies along the natural pathway of Indo-Pacific taxa spreading in the Mediterranean Sea via the prevailing currents, it may easily have spread in the area via the Suez Canal. Alternatively, its presence in Lebanon may be related to ship-mediated transport. Whatever is true, further fieldwork is necessary to evaluate the current status of this alien species in Lebanese waters and the Mediterranean Sea and its impacts on the local benthic communities.

Figures

Fig. 4: Turbo radiatus from Saksakiyeh (Lebanon). A) Live specimen in the tide pools of the vermetid reef. B) Ventral and dorsal view of one of the specimens sampled (total height ~4.1 cm).