Diversity of the diatom genus Pseudo-nitzschia Peragallo in the Quoddy Region of the Bay of Fundy, Canada

Representative species of the genus Pseudo-nitzschia are well established in the Bay of Fundy and are frequent contributors to the phytoplankton community of the Quoddy Region. This manuscript documents for the first time the specific diversity of this genus in the Quoddy Region. At least seven species of Pseudo-nitzschia are present in our samples, five of which represent new records for the region. These new records include: Pseudo-nitzschia americana, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia multiseries, Pseudo-nitzschia pungens and Pscudo-nitzschia subpacifica. The rarest and least known species is P. americana, while the most morphologically diverse one is Pseudo-nitzschia pseudodelicatissima (and P. pseudodelicatissima-like morphologies) known from the area since the 1930s, and includes both toxic and non-toxic varieties. Therefore, morphometrics, taxonomic discussion and distribution patterns are more completely documented for these two species. P subpacifica is the most recent addition to the local diversity of the genus. Pseudo-nitzschia seriata, earlier reported from the Bay of Fundy, was not observed in our samples. The presence of Pseudo-nitzschia delicatissima is confirmed, although a comparison with the narrow needle-shaped taxa reported earlier in the previous century is not possible. Five of the seven Pseudo-nitzschia species are now known to produce the neurotoxin domoic acid in various regions throughout the world, with P pseudodelicatissima producing domoic acid in the Bay of Fundy [Mar. Ecol. Prog. Ser. 67 (1990) 177]. Although analysis of morphology continues to be the most reliable method for species identification, surprisingly little is known about the specific range of natural morphological variability outside Europe. Here, we present morphological data for species detection in the Bay of Fundy and emphasize the differences between the Bay of Fundy populations and those from elsewhere. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.