Morphological variability in three populations of the dinoflagellate Alexandrium taylori

Water discolourations were observed in two localities of the NW Mediterranean (La Fosca and Palmira, Spain) during the summer of 1994 and 1995 caused by a non-toxic dinoflagellate belonging to the genus Alexandrium, subgenus Gessnerium. The organism was identified as Alexandrium taylori Balech, although differences were encountered compared to the original description from Arcachon (France). Detailed studies of the 1' plate were conducted on the Spanish material and compared with specimens from the type locality. Differences reported here between the Spanish and French populations are considered to be within the range of the morphological variability of this taxon.