Genus: Cell body long, with a constriction at its center; each half-cell laterally straight or wavy; rings of spines at each peak of the waves (similar to Pleurotaenium nodosum or P. kayei); 2-4 arm-like projections at each end; chloroplasts consisting of a central rod and radial laminae; pyrenoids aligned at the rod (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Cell body 206- (310-360) -668 μm long, (20-28) -53 μm wide (including spines), L/W=10-15; semicells not swelled at base, slightly tapered at terminal, wavy lateral margin with short spines, 2 arm-like projections at each end, each projection equipped with two spines; cell wall smooth; axial chloroplasts with radially-arranged laminae (Illustrations of The Japanese Fresh-water Algae, 1977).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Images of collecting locality: Block 2-4, Kashibaru marsh, Karatsu city, Saga Pref., Japan, September 9, 2008 by Y. Tsukii