Genus Vampyrella West 1901, emend. Hess et al. 2012
Diagnosis: Exclusively heterotrophic, naked, phagotrophic amoeboid organisms; life cycle includes amoeboid, freemoving trophozoites alternating with an obligatory digestive cyst, in which cell division usually take place; several taxa can fuse to form plasmodia and reach considerable sizes; sexual processes unknown; cytoplasm often differentiated into a finely granular, sometimes highly vacuolated part and structureless hyaloplasm, the latter often surrounding the main cell body, but at least constituting the pseudopodia; free-living in freshwater, soil, or marine environments.
This very instructive and beautiful video was made by Norbert Hülsmann and shows the development and mode of nutrition in Vampyrella lateritia, with following comment: "There are three strains of Vampyrella lateritia which are known to feed on green algae. One attacks Spirogyra, a second Closterium and the third Mougeotia. V. lateritia bores a hole through the algal cell wall and surrounds the protoplast with an ingestion pseudopodium. Vampyrella encysts after phagocytosis has been completed. Vegetative swarmers are subsequently released from the cyst."