Presented are results of morphological (LM and SEM) and taxonomical investigations on very small-sized Navicula spp. from the brackish waters of the Gulf of Gdansk and some freshwater affluents. Detailed studies revealed that most of the taxa in question are either new for science or previously described but rather poorly known. Dominant in that assemblage of extraordinarily small-celled Navicula species, specimens mostly below 10 μm in length, are Navicula germanopolonica WITKOWSKI & LANGE-BERTALOT and Navicula paulschulzii WITKOWSKI & LANGE-BERTALOT as established taxa. New for science are Navicula aleksandrae, Navicula bozenae and Navicula viminoides ssp. cosmomarina. From common freshwater habitats no species are known that could be confused with the new taxa.
Lange-Bertalot, H., Witkowski, A., Bogaczewicz-Adamczak, B., & Zgrundo, A. (2003). Rare and new small-celled taxa of Navicula s. str. in the Gulf of Gdansk and in its freshwater affluents. Limnologica, 33(4), 258–270. https://doi.org/10.1016/S0075-9511(03)80021-X