Species [ var. granatum ]: Cell body small in size, (22.5-39)-47 μm long, (15.4-24)-30 μm wide, isthmus (5.6-8.6)-9 μm wide, L/W=1.7, isthmus (5.6-8.6)-9 μm wide; semicells pyramidal in shape, apex slightly flattened, side view elliptical ovoid, apical view elliptial; cell wall dotted. [ var. subgranatum ]: Upper half of lateral margins wavy; 24-30 μm long, 17-22 μm wide, isthmus 6-9 μm wide. [ var. ocellatum ]: A small pore present at the center of semicells, 38-44 μm long, 26-28 μm wide, isthmus 6-9 μm wide (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: a marsh pond near Meigetsuso (Refuge), North of Higashidaiten, Azuma mountains, Yonezawa city, Yamagata Pref., Japan, July 1, 2007 by Y. Tsukii