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 Gonyaulax fragilis; whereas, in New Zealand mucilage events were linked to Gonyaulax hyalina. In summer 2012, during a ‘mare sporco’ event in the Gulf of Naples (Mediterranean Sea), numerous cells of a species tentatively identified as Gonyaulax hyalina 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 morphological features. Partial small subunit and large subunit rDNA regions of the three strains were identical. Based on these results and on a revision of the taxonomic history of the two taxa, we propose that G. fragilis and G. hyalina are the same species. Gonyaulax fragilis was described as Steiniella fragilis by Schütt in 1895 and transferred to G. fragilis by Kofoid in 1911. Gonyaulax hyalina was described a few years later by Ostenfeld and Schmidt in 1901. Thus, the name G. fragilis has priority, while G. hyalina is to be considered a synonym.

Key Words::

• Gonyaulax fragilis
• Gonyaulax hyalina
• HABs
• LSU
• Mare sporco
• Marine slime
• Mucilage
• SEM
• SSU

ACKNOWLEDGEMENTS

This research was funded by the Project Ostreopsis (Assessorato alla Sanità, Campania Region). L. Escalera's postdoc fellowship was funded by the Spanish Ministry of Education (MEC) within ‘Programa Nacional de Movilidad de Recursos Humanos del Plan Nacional de I+D+i 2008–2011’; We thank Roberta Piredda for the molecular analysis support, Franco Iamuno (Electron Microscopy service, SZN) for the SEM technical support and Carmen Minucci and Ferdinando Tramontano for culture maintenance and technical support.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/PH17-64.1.s1.