The Dinoflagellata (syn. Dinophyceae) contain either numerous yellow-brownish plastids or none. 2 flagellae, one of which longitudinally and the other transversally undulating. Frequently, the cells are subdivided by a sulcus and the annulus, the latter separating the upper epi- from the lower hypoconus (see e.g. Ceratiumimages). Complex shell with most diverse shapes and often trichocyst-like "extrusomes". Dioptric stigms as light sensors. Dinoflagellates exhibits all kinds of food behaviour: photoautotrophy, heterotrophy and there free-living or parasitic, partially osmotroph. Some species can occur in blooms and may then account for severe intoxication (e.g. Gymnodiniumand Gonyaulaxblooms). Noctilucaspecies are bioluminescent and elicit the "Meeresleuchten". Of eminent importance are dinoflagellates as zooxanthellae in corals, radiolaria and foraminifers. |