Lessardia elongata Saldarriaga & Taylor is identified for the first time in the north-western Black Sea in the present study. This species has probably been recorded with different names in the Black Sea due to lack of detailed investigations with scanning electron microscopy (SEM) or fluorescence microscopy. Our identification is based on observations with an electron microscope in September 2004 and with an epifluorescence and light microscope in June 2006. Cells were 5–10 µm wide, 22–30 µm long in formaldehyde fixed samples, fusiform, transparent, and had a faint broad girdle. Epitheca was slightly larger than the hypotheca and recently ingested prey could often be seen in the antapical half of the cell within very conspicuous vacuoles. Thin and faint thecal plates were hardly visible under epifluorescence microscope after staining the cells with fluorescence brightener 28 in the fixed samples. Cell abundances up to 18,400 cells l–1 and 87,000 cells l–1 were observed in September 2004 and June 2006, respectively.
