Gonyaulax hyalina and Gonyaulax fragilis (Dinoflagellata), two names associated with ‘mare sporco', indicate the same species

Abstract Aggregates of mucilaginous material have been at times observed in coastal and oceanic sea waters. In the Adriatic Sea ( Mediterranean Sea), these events have been known since the 18th century as ‘mare sporco' (= dirty sea), and in recent years, they have been associated with the dinoflagellate Gonyaulaxfragilis; whereas, in New Zealand mucilageevents were linked to Gonyaulaxhyalina. In summer 2012, during a ‘mare sporco' event in the Gulf of Naples ( Mediterranean Sea), numerous cells of a species tentatively identified as Gonyaulaxhyalina were detected in the mucilaginous aggregates. Since the boundary between G. fragilis and G. hyalina was not clear, we compared a strain isolated from the Gulf of Naples in 2012 with two strains from the Adriatic Sea and New Zealand waters, the latter two identified as G. fragilis and G. hyalina, respectively. Detailed light microscopy and scanning electron microscopy observations of the three strains showed that all shared the same thecal plate pattern and m...