Finding of the macrophagous deep-sea ascidian dicopia antirrhinum monniot, 1972 (Chordata: Tunicata) in the Tyrrhenian sea and updating of its distribution

Abstract

This study reports the in situ observations of a deep-sea ascidian, Dicopia antirrhinum (family Octacnemidae), on the deep seabed off the Aeolian Islands (Tyrrhenian Sea), between 569 and 813 m depth. These observations represent the first record of the species in Italian waters and the second observation in vivo to date. Peculiar macroscopic features are described here and the main differences from other species of the family Octacnemidae are highlighted, in order to allow the future identification of D. antirrhinum through visual technologies such as remotely operated vehicles. A total of 29 specimens were observed, with a maximum density of 0.012 specimens/m2. The global geographic and bathymetric distribution of D. antirrhinum known so far is also updated and discussed.