Pompholyxophrys ovuligera (Penard, 1904) Roijackers & Siemensma, 1988

Diagnosis: Cells covered with a layer of hollow, ovoid scales. These scales are 0.7-3.2 µm in diameter, without any internal struts. Ca. 10 beads per micrometer on the cell surface. Air-dried scales easily collapse. This species must be carefully distinguished from P. stammeri, which has also ovoid scales, as seen from above. In side view, the difference is obvious: scales of P. ovuligera have distinctly convex sides, whereas the distal and proximal layer of the scales of P. stammeri run nearly parallel.

Habitat: freshwater. Europe