Protozoa Guide review

Cymbomonas

genus / PYRAMIMONADALES / HALOSPHAERACEAE

Description

Bilaterally symmetrical cells with an apical depression surrounded by a horseshoe-shaped ridge . Four flagella emerge from the depressio n near the inner part of the horseshoe. With pa ri etal chloroplast containing a pyrenoid in the posterior PRASINOPHY part. An eyespot is located on the pyrenoid surface . The cell body covered with a continuous layer of very small square scales overlain by 2 layers of regularly arranged larger ones. Flagella covered with square underlayer scales overlain by limuloid scales. Two almost opposite rows of hair-shaped scales are also present. Cymbomonas is unusual in its swimming mode which includes rapid swimming with the flagella held behind the cell and more slow swimming with the flagella anterior but directed backwards along the cell. Three species described, but only one is well known. See Throndsen (1988). chloroplast ; f, flagellum ; g, Golgi body ; I, lipid body m, mitochondrion ; n, nucleus; p, pyrenoid; r, rhizoplast ; re , reservoir; s, eyespot; ss, starch sheath . x2500 . (From Parke and den Hartog-Adams , 1965) Cymbomonas . tetramitiformis Schiller, 1913 (Fig. 5) . Cells almost isodiametric , 12-16 11m in diameter. Large body scales square. Two additional scale types present on the cell near the flagellar bases, one type small and elongate , the other complex plates (Throndsen, 1988; Moestrup , Inouye and Hori , unpubl.). Throndsen ( 1 9 8 8) illustrates food vacuoles in this species , indicating mixotrophy. Very widely distributed marine flagellate.

Type species

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Raw text

Bilaterally symmetrical cells with an apical
depression surrounded by a horseshoe-shaped
ridge . Four flagella emerge from the depressio n
near the inner part of the horseshoe. With pa ri etal
chloroplast containing a pyrenoid in the posterior
PRASINOPHY
part. An eyespot is located on the pyrenoid surface .
The cell body covered with a continuous layer of
very small square scales overlain by 2 layers of
regularly arranged larger ones. Flagella covered
with square underlayer scales overlain by limuloid
scales. Two almost opposite rows of hair-shaped
scales are also present. Cymbomonas is unusual in
its swimming mode which includes rapid swimming
with the flagella held behind the cell and more slow
swimming with the flagella anterior but directed
backwards along the cell. Three species described,
but only one is well known. See Throndsen (1988).
chloroplast ; f, flagellum ; g, Golgi body ; I, lipid body
m, mitochondrion ; n, nucleus; p, pyrenoid; r,
rhizoplast ; re , reservoir; s, eyespot; ss, starch
sheath . x2500 . (From Parke and den Hartog-Adams ,
1965)
Cymbomonas . tetramitiformis Schiller, 1913 (Fig.
5) . Cells almost isodiametric , 12-16 11m in
diameter. Large body scales square. Two additional
scale types present on the cell near the flagellar
bases, one type small and elongate , the other
complex plates (Throndsen, 1988; Moestrup ,
Inouye and Hori , unpubl.). Throndsen ( 1 9 8 8)
illustrates food vacuoles in this species , indicating
mixotrophy. Very widely distributed marine
flagellate.