epicone (anterior half) longer than hypocone (posterior half)
eyespot sometimes present
chloroplasts numerous, blue-green
Nusuttodinium aeruginosum
I could detect Nusuttodinium aeruginosum (previously Gymnodinium aeruginosum) up to now exclusively in Ulmisried. The species can be identified easily by the blue-green color. In fact, Nusuttodinium aeroginosum is a colorless species. The chloroplasts, which give the cell its blue-green coloration, were “stolen” from photosynthetic prey organisms. Such stolen chloroplasts are also called kleptoplasts. It could be proved that Nussuttodinium aeroginosum obtains these kleptoplasts from Chroomonas. The cells of the prey organisms are completely digested except for the chloroplasts. These are then incorporated into the peripheral cell layer and kept alive.
In the literature, the species is described without an eyespot. I could detect an eyespot in some specimens (s. Fig. 1 and Fig. 5). Thus, the species seems to be quite variable not only with respect to the cell shape.
Fig. 1: Nusuttodinium aeruginosum. Overview of a mass occurrence. Note the two cells with an eye spot. Obj. 40 X.
Fig. 2 a-b: Nusuttodinium aeruginosum. L = 42 µm. Two focal planes of the freely swimming specimen. KLP = Kleptoplasts (“stolen” chloroplasts from photosynthetic prey). Obj. 100 X.
Fig. 3 a-b: Nusuttodinium aeruginosum. L = 39 µm. A second specimen slightly squashed. Nu = nucleus. Obj. 100 X.
Fig. 4: Nusuttodinium aeruginosum. A specimen in the state of a starting cell division. F = flagellum, ES = eye spot. Obj. 100 X.