Pseudoraphidocystis umbraculiformis (Dürrschmidt, 1987) Mikrjukov, 1997
Diagnosis: Periplast 15-25 µm in diameter, with two types of scales; details of protoplast unknown. Spine-scales are umbrella-shaped, 2.4 µm in diameter, with a short stalk, 0.6µm. Delicate radial ribs ornament the umbel and become blurred towards the centre. Plate-scales, 1.5 X 0.8 µm, are elliptical, sometimes slightly curved, smooth, with a poorly-developed axial thickening.
Distribution: Freshwater marshes. Chile, Germany, Japan (Dürrschmidt, 1987).