Genus: Test chitinous, coloured greyish-rose or deep purple, nearly allways rough with adhering sand-grains; pseudostome narrow, elliptic, notched in lateral view, frontal view of pseudostome more or less convex or truncated, with rounded corners; (Cash, The British Freshwater Rhizopoda and Heliozoa vol. II, 1909). Species [ var. petricola ]: Test variable in shape, 80-100 μm long; lateral margins straight or slightly convex; pseudostome linear or elliptic. [ var. major ]: Test colorless or lightish grey, 120-125 μm long; lateral margins nearly straight; pseudostome slightly less covex, but narrowed; (Cash, The British Freshwater Rhizopoda and Heliozoa vol. II, 1909).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.1, Shirakaba-Yachi, Komado marsh (No.6), Showa village and Tajima town, Fukushima Pref., Japan, May 21, 2007, by Y. Tsukii