Species: Cell body 24-40.5 μm long, 21-36.5 μm wide, isthmus 8.4-16 μm; semicells slightly twisted with each other; apical view triangular with each margin slightly convexed; side view elliptical diamond-shaped; cell wall covered with granules regularly arranged around each arm (Illustrations of The Japanese Fresh-water Algae, 1977).

50 μm 100 μm 150 μm; x 400

Staurastrum punctulatum [Brébisson] Ralfs var punctulatum: Body (24-34)-405 μm long, (21-31)-365 μm wide, constriction (84-15)-16 μm wide; body length slightly longer than width; hemicells twisted each other; hemicells laterally ellipsoidal, apically triangular with rounded corners; cell wall granulated (Illustrations of The Japanese Fresh-water Algae, 1977)

Staurastrum punctulatum f minor W et G S West: Body 224 μm long, 224 μm wide, constriction 7 μm wide; (Illustrations of The Japanese Fresh-water Algae, 1977)

Staurastrum punctulatum var kjellmani Wille: Body (28-34)-43 μm long, (224-266)-375 μm wide, constriction (98-11)-20 μm wide; the opening between the hemicells large nearly 90 degree; 3 corners broadly rounded not pointed (Illustrations of The Japanese Fresh-water Algae, 1977)

Staurastrum punctulatum var pygmaeum [Brébisson] Ralfs W et G S West: Body 27-(31-364)-42 μm long, 24-(28-336)-40 μm wide, constriction 9-(11-14)-18 μm wide; the opening between the hemicells slightly larger than that of S punctulatum var punctulatum; cell wall granulated but more spiny (Illustrations of The Japanese Fresh-water Algae, 1977)

Staurastrum punctulatum var subproductum W et G S West: Body 308-31 μm long, 334 μm wide, constriction 85-(10) μm wide; the corners of hemicells rather pointed (Illustrations of The Japanese Fresh-water Algae, 1977)