Pterocystis discoidea (Dürrschmidt, 1985)
Diagnosis: Periplast 10-15 µm, protoplast unknown; spine-scales circular or broad oval, 3.41-4.1 µm in diameter, dish-shaped with a broad structureless border and a central part with radiating ribs; emitted from a strongly rudimentary shaft; plate-scales relatively small, elliptical and thin 0.75 X 0.6 -1.1 µm; central rib slightly shifted to one pole.
Ecology: only known from Sphagnum and a small pond. Chile (Dürrschmidt, 1985), Germany (Eckhard Voelcker, 2014, pers. comm.)