Stylodinium littorale, a new marine dinococcalean alga (Pyrrhophyta)

Abstract Stylodinium littorale, a new dinophycean species found in the sand of seashores in subtropical and tropical regions in Japan and adjacent waters, is described. The organism has a life cycle in which a stalked and non-motile phase alternates with a free and motile phase whose shape is that of the typical gymnodinioid swarmer. The non-motile phase is unicellular, stalked and globose in shape, with many discoid chloroplasts peripherally situated and a typical dinophycean nucleus. The cell body is enclosed by a theca with the following plate tabulation: pp, 5′, 2a, 7″, ×, 5c, 6s, 5′″, lp, 1″″. The motile cell has a theca composed of thin plates which could not be specified in this study. The organism reproduces asexually by the formation of two zoospores or aplanospores within the cell body. Sexual reproduction is unknown. In many respects, S. littorale is similar to certain members of Stylodinium in the family Phytodiniaceae, in its gross morphology, method of reproduction and type of life cycle, bu...