Family Vampyrellidae Zopf, 1885 emend. Hess et al, 2012
Diagnosis: Limnetic Vampyrellida; predominantly showing the isodiametric morphotype in the trophic phase. Exhibiting straight, tapering and occasionally branching filose pseudopodia. Trophozoites of known members perforate algal cell walls (e.g. of Zygnematophyceae or Chlorophyceae) and phagocytose only the cell contents; thus seemingly strictly specialized on the food organisms. Cells show intense orange colour due to the algal diet, except directly after phagocytosis when the cells are green. Digestive cysts isodiametric, sometimes slightly flattened; at least two distinct cyst envelopes present; a delicate outer cyst envelope usually attaches the cyst to a substrate (e.g. the food alga), occasionally forming a stalk. The family can be phylogenetically defined as the largest well supported clade within the Vampyrellida including Vampyrella, but excluding Leptophrys (previously described as Vampyrella vorax).
Genera included: Vampyrella