Species: Cell body medium in size, broadly elliptical, 40-(45-48)-53 μm long, 32-(37-40)-44 μm wide, isthmus 14-(16-18)-21 μm wide; semicells semicircular in shape, basal corners right-angled, 6 lines of apically-truncated warts (about 14 warts in each line) present along their margins; 2 lines of warts or granules (upper 3 & lower 4) present at the center of the semicells (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.8, a marsh pond at Sensho-ga-hara, near Akita-komagadake (mountain), Shizukuishi town, Iwate Pref., Japan, August 6, 2007 by Y. Tsukii