Genus: Colonies of 4 (or 2, 8, 16) cells attached side by side, arranged linearly or zigzag; cell body elliptical or spindle or crescent in shape; terminal cells with spiny projections in many species; cell wall usually smooth, but in some species granulated or dented or ridged (Illustrations of The Japanese Fresh-water Algae, 1977).
Species: Colonies sometimes surrounded by mucilage; cell body cylindrical to spool-shaped, with broadly rounded ends and slightly concave sides, 10-21 μm long, 3-8 μm wide; cells arranged in a linear series contacting at the polar regions of the sides making intercellular perforation between the cells; outer cells with slightly convexed outer side and a long, slightly curved spine at each corner; cell wall smooth or punctate (Photomicrographs of the Freshwater Algae, vol. 16, 1996).
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S. perforatus cell 19 x 5 μm L/W=3.8 S/L=0.8 Bessho-numa Saitama, 2001 |
S. perforatus cell 17 x 5 μm L/W=3.4 S/L=1.2 Koshigaya Saitama, 2001 |
S. perforatus cell 19 x 7 μm L/W=2.7 S/L=1.2 Japan, 1998 |
S. perforatus cell μm L/W= S/L= Chiba-Minato p. Chiba, 2003 |
S. perforatus or S. tropicus ? cell 32 x 10 μm L/W=3.2 S/L=0.8 Umi-no-nakamichi Fukuoka, 2001 |
S. perforatus or S. tropicus ? stock Ffu-1 cell 31 x 9 μm L/W=3.4 S/L=0.7 Umi-no-nakamichi Fukuoka, 2001 |
S. perforatus inner 28 x 11 μm outer 24 x 8-9 μm L/W=2.5-2.6 S/L=0.9-1.0 Tsuchiura Ibaraki, 2002 |
S. perforatus ? spines short cell 18 x 6 μm L/W=3.0 S/L=0.33 Tsuchiura Ibaraki, 2002 |
S. perforatus cell 20 x 6.5 μm L/W= S/L= Akigase Park Sakura-ku Saitama, 2004 |
S. perforatus cell 21 x 6 μm L/W= S/L= Imou bog Toyohashi Aichi, 2004 |
S. perforatus cell 19 x 6-8 μm L/W= S/L= Imou bog Toyohashi Aichi, 2004 |
S. perforatus cell 12-15 x 4 μm L/W= S/L= near Yamaguchi Univ. Yamaguchi, 2004 |
S. perforatus cell μm L/W= S/L= Chiba-Minato p. Chiba city Chiba, 2008  |
