A new species of a marine sand-dwelling dinoflagellate in the genus Sinophysis is described from South Brittany, France using both light and scanning electron microscopy. Cells of Sinophysis verruculosa sp. nov. are oval to subcircular, slightly bulging dorsally and flattened laterally, with no chloroplasts, ranging from 52.2 to 57.8 μm in length, and 43.2 to 51.0 μm in width. The epitheca is small and tilted back to the dorsal part of the cell. At least three major plates and smaller platelets form the epitheca, but the exact number cannot be ascertained due to their reduced size and the presence of a projection hiding the sutures. Four cingular and four hypothecal plates, two large lateral and two small ventral plates are present. The sulcus is bordered by lists supported by hypothecal plates and extends less than two-thirds of the total length of the hypotheca. The most distinctive feature of S. verruculosa is the minute verrucose ornamentation covering the thecal surface, which contrasts with the smooth and areolate ornamentation of temperate and tropical species, respectively.
©2009 by Walter de Gruyter Berlin New York