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: No. 4, Chigo-ike marsh at the top of Yakebitai mountain, Shiga highland (Oku-shiga highland), Yamanouchi town, Nagano Pref., Japan, October 9, 2006 by Y. Tsukii