Morphology and ecology of the marine benthic dinoflagellate Scrippsiella subsalsa (Dinophyceae)

The thecal surface morphology of Scrippsiella subsalsa (Ostenfeld) Steidinger et Balech was examined using the scanning electron microscope. This species is distinguished by a number of morphological characteristics. Apical plate 1' is wide, asymmetric, and pentagonal, and it ends 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 plate with thickened margins at plates 2', 3', and 4'. The intercalary bands are wide and deeply striated. The cingulum is deep, formed by six cingular 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 ribbon with a rounded tip that protrudes posteriorly, partially covering the 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 presented between S. subsalsa and other known Scrippsiella species.