Description
More or less bean-shaped cells with 2 unequal flagella inserted in the lateral invagination . The shorter flagellum directed anteriorly during swimm ing , th e longer trailing . Cells with a single plate-like chloroplast and a pyrenoid in a lateral position opposite the flagellar insertion. An eyespot is present in most species , located near the base of the short flag ellum . Freshwater species with a contractile vacuol e system near the flagellar bases. Cells covered with up to 7 types of scales: the flagella with an underlayer of square scales overlain by pairs of rod-shaped scales and in some species by small stellate ones. Two opposite rows of hair-shaped scales . The cell body with underlayer of small square scales overlain by 1 - 3 layers of other types . These are usually stellate and belong to several morphological types . The flagellar pit sometimes with a special type of hair-shaped 'pit-scale .' Sexual reproduction by hologamy reported in one species (Suda et al. , 1 9 8 9) . Geog raphically widespread in marine and freshwater plankton ; less than 10 species known . Nephroselmis olivacea Stein , 1878 (Fig . 1 9) . Cells flattened , 6-10 ~-t m long, 7-15 ~-tm wide, and 3-6 ~-t m thick . Short flagellum 1.5-2 times cell length , long flagellum 2-3 times cell length . Pyrenoid surrounded by 2 distinct starch grains . Flagella covered with 3 layers of scales in addition to hair-shaped scales. Cell body with scales in 4 layers, the three outer layers comprising stellate scales of 3 morphological types. Widespread organism in fresh water . SEB Moestrup and Ettl (1979) .
Type species
Figures
Raw text
More or less bean-shaped cells with 2 unequal flagella inserted in the lateral invagination . The shorter flagellum directed anteriorly during swimm ing , th e longer trailing . Cells with a single plate-like chloroplast and a pyrenoid in a lateral position opposite the flagellar insertion. An eyespot is present in most species , located near the base of the short flag ellum . Freshwater species with a contractile vacuol e system near the flagellar bases. Cells covered with up to 7 types of scales: the flagella with an underlayer of square scales overlain by pairs of rod-shaped scales and in some species by small stellate ones. Two opposite rows of hair-shaped scales . The cell body with underlayer of small square scales overlain by 1 - 3 layers of other types . These are usually stellate and belong to several morphological types . The flagellar pit sometimes with a special type of hair-shaped 'pit-scale .' Sexual reproduction by hologamy reported in one species (Suda et al. , 1 9 8 9) . Geog raphically widespread in marine and freshwater plankton ; less than 10 species known . Nephroselmis olivacea Stein , 1878 (Fig . 1 9) . Cells flattened , 6-10 ~-t m long, 7-15 ~-tm wide, and 3-6 ~-t m thick . Short flagellum 1.5-2 times cell length , long flagellum 2-3 times cell length . Pyrenoid surrounded by 2 distinct starch grains . Flagella covered with 3 layers of scales in addition to hair-shaped scales. Cell body with scales in 4 layers, the three outer layers comprising stellate scales of 3 morphological types. Widespread organism in fresh water . SEB Moestrup and Ettl (1979) .