Genus: Cell body short, radiate in shape; apical view of the cell, triangular, polygonal, ellipsoidal or spindle-shaped; zygospores formed outside of mother cells (Illustrations of The Japanese Fresh-water Algae, 1977) Subgenus: lacks arm-like projections (Illustrations of The Japanese Fresh-water Algae, 1977) Species (var. bidentatum): cell body excluding spines 31-62 μm long, 37-64.5 μm wide (excluding spines), constriction 11-26.5 μm wide, (Illustrations of The Japanese Fresh-water Algae, 1977)

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Ushidome-ike (pond), Norikura highland, Azumi, Matsumoto city, Nagano Pref., Japan, November 4, 2007 by Y. Tsukii