Description
Cells discoid in ventral view; pronouncedly flattened dorsoventrally with dorsal surface concave and ventral surface convex , giving a structure resembling a saddle or a turtle's carapace ; flagella arise from a shallow groove on the ventral surface ; anterior flagellum somewhat longer than the cell , trailing flagellum is shorter, being of the same length as the cell or less; the beat of the anterior flagellum causes cell to move forward smoothly, without rotation ; discoid chloroplasts, 5-13 in number with 6 being common, in peripheral layer , yellowish-green in color ; mucocysts absent. See Fukuyo et al . (1990); Hara et al. (1985). by 5-7 ~m thick; only species of the genus ; has been confused with Heterosigma akashiwo, which has similar size , shape, and env i ronment, but the chloroplasts of 0/isthodiscus are greener, and it swims without rotating .
Type species
0listhodiscus luteus Carter, 1937 (Fig . 4). Cell 15-25 long x 10-16 wide
Figures
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Raw text
Cells discoid in ventral view; pronouncedly flattened dorsoventrally with dorsal surface concave and ventral surface convex , giving a structure resembling a saddle or a turtle's carapace ; flagella arise from a shallow groove on the ventral surface ; anterior flagellum somewhat longer than the cell , trailing flagellum is shorter, being of the same length as the cell or less; the beat of the anterior flagellum causes cell to move forward smoothly, without rotation ; discoid chloroplasts, 5-13 in number with 6 being common, in peripheral layer , yellowish-green in color ; mucocysts absent. See Fukuyo et al . (1990); Hara et al. (1985). by 5-7 ~m thick; only species of the genus ; has been confused with Heterosigma akashiwo, which has similar size , shape, and env i ronment, but the chloroplasts of 0/isthodiscus are greener, and it swims without rotating .