Paulsenella Chatton (Dinophyta), ectoparasites of marine diatoms: development and taxonomy

Abstract

All members of the dinophyte Paulsenella are ectoparasites on marine planktonic diatoms. At present three species are known, two of which are described here for the first time. The taxonomy of the type species, P. chaetoceratis, is paid critical attention. The species are clearly distinguished by their host specificity and additionally by differences in morphology, especially of the trophonts. Using clonal cultures the life cycles of the three species are compared. The vegetative development may be interrupted by formation of temporary and resting cysts. In ageing cultures, stages with nuclear cyclosis occur, believed to indicate meiosis. In P. vonstoschii, the meiospores are capable of developing into resting cysts. As yet, knowledge on sexual reproduction is still incomplete. © 1988 Biologische Anstalt Helgoland.