An investigation into the taxonomy and yellow-substance release by the marine dinoflagellate, Scrippsiella tinctoria
A new marine dinoflagellate species, Scrippsiella tinctoria sp. nov., is described using the thecal staining techniques of von Stosch (1969), and several changes in the taxonomy of related species are proposed. These changes include- 1) the retention of the specific name Scrippsiella areaaria and suppression of the recently proposed Scrippsiella hexapraecinqula as a superfluous epithet for S. Qreqaria1 2) the rejection of the dinoflagellate genus Ensiculifera as it is taxonomically invalid, and 3) the formation of the new genus Pentapharsodinium based on thecal tabulation and inferred plate homologies particularly of the Cingular plate series, cyst morphology, and cyst wall composition. Scrippsiella tinctoria and a marine chloromonad, Chattonella japonica, were found to release an ultraviolet� absorbing yellow-substance into solution. These substances are polyphenolic and have an ultraviolet absorption maximum at approximately 240 nm. It is probable that the yellow-substances released by these two species are slightly different in composition and are composed of several different polyphenolic compounds. The release of yellow-substance by S. tinctoria is an active secretion while the release by C. japonica may also be attributed to cell lysis. There is an increase in the amount of ye1low�substance released by S. tinctoria with increasing pH and increasing salinity. These secretions are very similar to the polyphenolic secretions of the Phaeophyta and most likely contribute to the Gelbstoff of seawater. Electron microscopy reveals that Scrippsiella tinctoria also possesses electron dense vesicles which are identical to the "physodes" of brown algae and are responsible for the accumulation of polyphenolic yellow-substance before it is released into solution. The physodes of S. tinctoria are formed adjacent to the chloroplasts and are bounded by a single membrane, presumably derived from the endoplasmic reticulum.