(Manguin) Hasle, Medlin & Syvertsen (1994: 265, figs 124–141, 142f, tab. 2)
Synedra fragilis Manguin (1957: 123, pl. 5, fig. 22)
[after Hasle et al. (1994)] Cells in stellate or pin-cushion-shaped colonies; apical axis 26–58 µm; transapical axis 3–4 µm. Valves lanceolate, with obtuse ends; smaller cells rhomboidal. Transapical striae parallel to slightly radiating, 21–24 in 10 µm, visible by LM. Areolae poroid, 50–60 in 10 µm. Each valve end with an apical field of 6 or 7 longitudinal slits through the valve wall. Labiate process solitary, externally rectangular, c. twice the size of an areola, located close to one valve end.
Type locality, Cape Margérie, Terre Adélie, 66°50’S 141°25’E (Hasle et al., 1994). We have not seen this species.
Some species formerly included in Fragilaria and Synedra have been transferred to Synedropsis on the basis of their valve striation, the occurrence and structure of labiate processes and apical pore (slit) fields and the nature of the girdle (Hasle et al., 1994). Synedropsis hyperboreoides and S. laevis were collected in the present study, and several other species, e.g. S. fragilis, S. recta, S. lata var. lata and S. lata var. angustata, have been described from Antarctic locations (Hasle, 1994).