Pompholyxophrys stammeri (Rainer, 1968) Roijackers & Siemensma, 1988
Diagnosis: Cell spherical, coated with one or two layers of elliptical, strongly compressed siliceous perles. Filopodia fine and short, emerging through the layer of perles. Cytoplasm usually reddish. Fast rolling movement.
Dimensions: Cell with periplast 27-66 µm; perles 2-6 µm.
Ecology: Fresh water; recorded from Europe and South-America. I have found this species at several locations in the Netherlands, usually in clear water, and in Southern Sweden.
Remarks: I doubt if this species can be distinguished light microscopically from P. stellata.
Literature: Siemensma (1991), Roijackers and Siemensma, 1988.