Species: Cell body elliptical, 50-(56-60) μm long, 42-(48-56) μm wide, isthmus 13-(15-17) μm wide, L/W=1.3; semicells pyramid-shaped with flattened apex, basal corner broadly rounded, both sides convex with wavy margin (about 10-13 waves or granules), apex flat (waves/granules absent); cell wall covered with uniformely arranged granules interspersed by small pores, side view elliptical; chloroplasts with 2 pyrenoids in each semicell (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Ushiku-numa Mizube park, Ryugasaki city, Ibaraki Pref., Japan, April 28, 2008 by Y. Tsukii