Species: Cell body small in size, 25.8-32.8 μm long, 25.8-33.6 μm wide, isthmus 7-11 μm wide; semicells elliptical diamond- or spindle-shaped in side view, upper side of lateral margins more convex than lower ones; apical view triangular with concaved margins, each corner truncated; cell wall covered with granules arranging circularly aroung the corners (Illustrations of The Japanese Fresh-water Algae, 1977)

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Nashi-ike (pond), Kagami-ishi town, Fukushima Pref., Japan, January 3, 2008, by Y. Tsukii