The Chrysomonadina (syn. Chrysophyceae) are small flagellates with
yellow-brownish plastids. This is due to the overlay of chlorophyll a by
fucoxanthine. Two flagellae with unequal length originate at the anterior
side, the longer of which is applied with two rows of stiff mastigonemes
while the shorter has only few hairy extensions. To survive inactive
periods, chrysomonads make endocysts bearing a single cell. Energy storage
material is chrysolaminarin (= polysaccharide leukosine) or oils, not
starch. In case of food scarcity, some species can switch to heterotropic
mode, making pseudopods to phagocyte other small protists. Chrysomonads
are inhabitants of both, limnic and marine systems. There are speculations
putting chrysomonads as the basic group for color-less flagellates,
rhizopods and multicellular algae. |