MORPHOLOGY AND ECOLOGY OF THE MARINE BENTHIC DINOFLAGELLATE SCRIPPSIELLA-SUBSALSA (DINOPHYCEAE)

The thecal surface morphology of Scrippsiella subsalsa (Ostenfeld) Ste idinger et Balech was examined using the scanning electron microscope. This species is distinguished by a number of morphological characteri stics. Apical plate 1' is wide, asymmetric, and pentagonal, and it end s at the anterior margin of the cingulum. Intercalary plates 2a and 3a are separated by apical plate 3'. The apical pore complex includes a large P-o plate with a raised dome at the center and a deep canal plat e with thickened margins at plates 2', 3', and 4'. The intercalary ban ds are wide and deeply striated. The cingulum is deep, formed by six c ingular plates; its surface is transversely striated and aligned with a row of minute pores. The cingular list continues around postcingular plate 1 ''' to form a sulcal list. The sulcal list is a flexible ribb on with a rounded tip that protrudes posteriorly, partially covering t he sulcal plates. The hypotheca is lobed, and the antapical plates are irregularly shaped and wide in antapical view. The thecal surface is vermiculate to reticulate. A comparison in morphology and ecology is p resented between S. subsalsa and other known Scrippsiella species.