Pompholyxophrys exigua (Hertwig et Lesser, 1874) Penard, 1904
Diagnosis: Cells with covering of scales 15-29 µm in diameter. Cells covered by a layer of small spherical scales, 0.8-3.2 µm in diameter. The scales of individual cells are more or less of uniform in size, differing from those of P. punicea, which vary in size. Air-dried scales are commonly dented, but it is not clear if these dented scales are commonly present in living cells or are the result of preparation procedures.
Observed habitat: freshwaters in The Netherlands and Sweden.