Description
Cells more or less compressed , often slightly curved but never twisted . Cells cordiform , elliptic, or almost spherical . Similar to and very closely related to Scherffelia , but differing in cell shape and in the presence of a single chloroplast ( very rarely 2) , a pyrenoid , and an eyespot. Asexual reproduction as in Scherffelia . Thick-walled cysts known in several species , but sexuality not reported . Many species described , but the taxonomy requires rev1s1on . Marine species of Carteria probably also belong to Tetraselmis . Total number of species probably less than 50 , distributed in both freshwater and marine biota , some species i n plankton , others benthic in green sand , or in symbiosis with metazoa, e.g . the turbella rian Convoluta roscoffensis (Provasoli et al. 1 968) . See Hori et al. (1982, 1983, 1986) . Tetrase/mis cordiform is (Carter) Stein , 1 8 7 8 (Figs. 17, 18). Cells 14-20 ~m long , 16-23 ~m wide , 9-13 ~m thick, flattened, elliptic , or nearly round when seen in side view. Flagellar length equal to or shorter than cell length . With cup-shaped chloroplast and a basal pyrenoid . Eyespot near the mid-region of the cell , 2 contractile vacuoles anteriorly . Cell wall distinct, sometimes slightly brownish or yellowish (Melkonian , 1 979 ) . Geographically widespread , in many types of freshwater . 1264 PRASINOPHYCEAE F The 1. Fla dir fla whole cell. Electron micrograph , x2500 . (From Parke ... and Manton, 1965). 1. Fla bac ... of cell showing chloroplast around periphery (with stroma starch) , pyrenoid (P) with cytoplasmic intrusions and starch shell , eyespot (arrow) , nucleus Fig . (N) , one of the Golgi bodies (G) , one of the flagella (F) around with scales, basal body and root to the nucleus , and the cv , c closely adpressed theca. x1 0 ,000. (From Manton and pyreno Parke , 1965). 1979) AMILY NEPHROSELMIDACEAE Skuja, 1948 ex P.C. Silva, 1980 cell body enclosed in several layers of scales . gella laterally inserted . Shorter flagellum ected anteriorly during swimming , longer gellum trailing. The flagella inserted at a wide le to each other.. .. ................ ..... . . ...................... .... ... ..... .... ... .. ... .. Nephroselmis gella inserted in the cell axis , both directed kwards during swimming , almost parallel ....... ...... .... .. ... ..... ..... ..... Pseudoscourfieldia 19. Nephroselmis olivacea ., a , a 2 , starch grains the pyrenoid ; b, unknown body; ch , chloropl ast; ontractile vacuole ; g, Golgi body; n, nucleus; p , id ; s, eyespot. x21 00 . (From Moestrup and Ett l , . PRASINOPHYCE
Type species
Figures
Raw text
Cells more or less compressed , often slightly curved but never twisted . Cells cordiform , elliptic, or almost spherical . Similar to and very closely related to Scherffelia , but differing in cell shape and in the presence of a single chloroplast ( very rarely 2) , a pyrenoid , and an eyespot. Asexual reproduction as in Scherffelia . Thick-walled cysts known in several species , but sexuality not reported . Many species described , but the taxonomy requires rev1s1on . Marine species of Carteria probably also belong to Tetraselmis . Total number of species probably less than 50 , distributed in both freshwater and marine biota , some species i n plankton , others benthic in green sand , or in symbiosis with metazoa, e.g . the turbella rian Convoluta roscoffensis (Provasoli et al. 1 968) . See Hori et al. (1982, 1983, 1986) . Tetrase/mis cordiform is (Carter) Stein , 1 8 7 8 (Figs. 17, 18). Cells 14-20 ~m long , 16-23 ~m wide , 9-13 ~m thick, flattened, elliptic , or nearly round when seen in side view. Flagellar length equal to or shorter than cell length . With cup-shaped chloroplast and a basal pyrenoid . Eyespot near the mid-region of the cell , 2 contractile vacuoles anteriorly . Cell wall distinct, sometimes slightly brownish or yellowish (Melkonian , 1 979 ) . Geographically widespread , in many types of freshwater . 1264 PRASINOPHYCEAE F The 1. Fla dir fla whole cell. Electron micrograph , x2500 . (From Parke ... and Manton, 1965). 1. Fla bac ... of cell showing chloroplast around periphery (with stroma starch) , pyrenoid (P) with cytoplasmic intrusions and starch shell , eyespot (arrow) , nucleus Fig . (N) , one of the Golgi bodies (G) , one of the flagella (F) around with scales, basal body and root to the nucleus , and the cv , c closely adpressed theca. x1 0 ,000. (From Manton and pyreno Parke , 1965). 1979) AMILY NEPHROSELMIDACEAE Skuja, 1948 ex P.C. Silva, 1980 cell body enclosed in several layers of scales . gella laterally inserted . Shorter flagellum ected anteriorly during swimming , longer gellum trailing. The flagella inserted at a wide le to each other.. .. ................ ..... . . ...................... .... ... ..... .... ... .. ... .. Nephroselmis gella inserted in the cell axis , both directed kwards during swimming , almost parallel ....... ...... .... .. ... ..... ..... ..... Pseudoscourfieldia 19. Nephroselmis olivacea ., a , a 2 , starch grains the pyrenoid ; b, unknown body; ch , chloropl ast; ontractile vacuole ; g, Golgi body; n, nucleus; p , id ; s, eyespot. x21 00 . (From Moestrup and Ett l , . PRASINOPHYCE