Variable in shape; strong constriction at center; semicell ellipsoidal, polygonal, etc.;
cell wall with simple or branching spines, most of them laterally aligned;
4 plate-like chloroplasts in each semicell; one or more pyrenoids in each chloroplast
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species: Cell body (without spines) 43-80 μm long, 43-53 μm wide, isthmus 13-14 μm wide, semicells with two anterior, two lateral, one basal spines, with a centrally located large granule surrounded by about 10 small granules (Illustrations of the Fresh-water Algae, 1977).
Images of collecting locality:
No.2, Ohyachi, Akita-Hachimantai, Kazuno city, Akita Pref., Japan, September 21, 2007 by Y. Tsukii