Report | September 26, 2018

After Scilla and Cariddi, another uncommon animal recorded in Sicilian waters: the deep-sea carnivorous ascidian Dicopia antirrhinum C. Monniot, 1972

Nowadays the knowledge about the Mediterranean deep-sea fauna is still scarce, especially concerning Ascidiacea. Unlike their shallow counterparts, deep-sea ascidians are rather uncommon to find. Visual technologies, such as Remotely Operated Vehicles (ROVs), represent a unique opportunity to observe several rare or uncommon species in their natural habitat. This study reports the occurrence of a rare deep-sea ascidian, Dicopia antirrhinum C. Monniot, 1972 (family Octanemidae), on the deep seabed off Aeolian Islands (Tyrrhenian Sea). This species was firstly found in 1975 off Malta (Sicily Channel) at 500 m depth, with only juvenile specimens. Afterwards, in 2011, few specimens of D. antirrhinum were observed and sampled in La Fonera canyon (Balearic Sea) at 1100 m depth. Our observation (23 specimens in total) represents the first record in Italian waters. In particular, D. antirrhinum was found at Eolo seamount (2 specimens; 760 m depth), at Filicudi bank (4 specimens; 643–870 m depth), off Secca del Capo (11 specimens; 568–761 m depth), around Lipari (1 specimen; 807 m depth) and off Stromboli (5 specimens; 662–812 m depth). The presence of macroscopic diagnostic characters, such as the body shape and the peculiar lip-like siphons, allowed the specific identification from ROV images.

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