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Euglenophyceae: Euglenales (or Colaciales)

Colacium vesiculosum
Ehrenberg, 1833

Colacium Genus: Cell body attached to others by gelatinous stalk emerging from anterior end; cell division occurs on the stalk forming dichotomously branching colony; pellicles soft but euglenoid movement rare; chloroplasts soucer-shaped in some species examined; a pyrenoid present at the center; a canal opened near anterior end; stigma present (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).
Species: Cell body ovoidal or spindle-shaped, posterior end rounded, 19-30 μm long, 10-12 μm wide; swimmers also ovoidal or spindle-shaped; chloroplasts soucer-shaped with a pyrenoid, 5-10 in number; a locomotive flagellum about 2 times longer than the cell body; nucleus spherical 6-7 μm in diam., stigma 3-4 μm (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).
Similar genus -->> Characium (Chlorophyta); Characiopsis (Heterokonta);
Similar species -->> C. libellae


Colacium vesiculosum, cell body 17 μm long, 9 μm wide, repeating slow contraction, x 640, Toneri Park, Adachi-ku, Tokyo, Japan, December 2001 by Y. Tsukii
scale 50 μm scale 100 μm scale 150 μm; x 400 : scale 31 μm scale 63 μm scale 94 μm; x 640
Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum
Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum Colacium vesiculosum


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