Family: Colonies of a fixed number of cells (4, 8, 16, 32, or more) arranged 2- or 3-dimensionally; cells spherical, ellipsoidal, polygonal, etc. in shape; chloroplasts 1 or several, plate-like in shape, with 1 pyrenoid; asexual reproduction by autocoenobium (Illustrations of The Japanese Fresh-water Algae, 1977).
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).
Google Image Search
| Cells with long spines: S= length of Spines; L=Body length | |||
S. longispina 5 samples S/L=2.4 2001-2006 |
S. maximus 8 samples S/L=0.6-1.0 1997-2005 |
S. quadricauda = S. communis 62 samples S/L=0.6-1.2 1998-2006 |
S. ellipsoideus 17 samples S/L=2 1999-2006 |
S. protuberans 18 samples S/L=0.8-1.2 199?-2006 |
S. opoliensis 6 samples S/L= 2001-2008 |
S. bicaudatus 6 samples 1998-2002 |
S. insignis stock Ito-2 10 x 4 μm Tsuchiura Ibaraki, 2002 |
S. abundans 21 samples 1998-2007 |
S. perforatus 13 samples 17-32 x 5-10 μm S/L=0.8-1.2 1998-2008 |
S. quadrispina 6 samples 13-16 x 5-6 μm S/L=0.5-0.9 2001-2005 |
S. intermedius 1 sample cell 8.5 x 4 μm S/L=1.5 Tokyo, 2001 |
Scenedesmus ?? cell μm Saitama, 1999 |
Scenedesmus ?? many spines ! similar to Chodatella Saitama, 2001 |
Scenedesmus sp. cell μm Someino p.s. Sakura Chiba, 2008  |
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| Cells with short spines or granulated | |||
S. denticulatus 21 samples 11-20 μm 1997-2008 |
S. polydenticulatus 2 samples μm Japan, 2001 |
S. lunatus 6 samples μm 1999-2003 |
S. longus 13 samples μm 1998-2008 |
S. microspina 3 samples μm 2003-2004 |
S. curvatocornis ? cell μm Tokyo, 2001 |
S. verrucosus granu. at both ends cell μm Mizumoto park Tokyo, 2001 |
S. verrucosus granu. at both ends Ochiai-numa 1 Noshiro Akita, 2007 |
| Cell body with longitudinal ridges or with longitudinal rows of dented projections | |||
S. brasiliensis 16 samples 11-22 x 2.5-7 μm 1999-2007 |
S. armatus 20 samples μm 1999-2007 |
S. acutiformis 3 samples 2002-2004 |
S. carinatus 9 samples long spines and ridges 2001-2006 |
S. serratus lateral spines Tochigi, 2000 |
S. serratus lateral spines Nasu-shiobara Tochigi, 2005 |
S. serratus near Omine Mt. Minakami Gunma, 2007 |
S. costatus = Enallax costatus 4 samples 16-22 x 7 μm 2004-2008 |
S. circumfusus v. circumfusus 3 samples 2003-2006 |
S. circumfusus v. bicaudatus 3 samples 2003-2006 |
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| Spines and ridges absent; cell body spindle-shaped (or pear-shaped) | |||
S. acutus 20 samples 1997-2006 |
S. incrassatulus 9 samples 1999-2004 |
S. incrassatulus ?? 12.5 x 5.5 μm L/W=2.3 Uruguay, 1999 |
S. tibiscensis 4 samples L/W=3.2 2000-2004 |
S. producto-capitatus or S. pseudobernardii ? 4 samples 2001-2004 |
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| Spines and ridges absent; cell body ellipsoidal or ovoidal | |||
S. ecornis 20 samples inner space absent cell ellipsoidal 1998-2006 |
S. arcuatus 12 samples inner space present cell reniform 1999-2008 |
S. ovalternus or S. obtusus ? 6 samples cells zig-zag 1999-2005 |
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| Spines and ridges absent; cell body crescent in shape | |||
S. acuminatus 42 samples cell 9-62 μm 1997-2008 |
S. bernardii 3 samples cell 15-17 μm 1999-2003 |
S. javanensis 6 samples 28-38 x 5 μm 2001-2006 |
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| Scenedesmus or other speices ?? | |||
Scenedesmus ?? or Chodatella ? cell 8 x 4.5 μm Saitama, 2000 |
Scenedesmus ?? cell 9-10 x 5 μm L/W=1.8-2.0 Tochigi, 2001 |
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