(Hendey) Paddock (1988: 86, pl. 31)
Navicula planamembranacea Hendey (1964: 188, fig. 8)
Hasle & Syvertsen (1997: 284, pl. 64)
Cells usually solitary, flattened transapically, usually seen in girdle view, weakly silicified and often collapsed; apical axis 66–90 µm; transapical axis 8–10 µm; pervalvar axis 15–30 µm. Transapical striae fine, 28–30 in 10 µm; striae near the centre of cell visible by LM (Fig. b). Raphe located on a raised flat valve surface, dividing the valve into 2 unequal sides. Central nodule slightly depressed (Fig. a, b). Raphe fins small, located near valve ends on either side of the nodule. Chloroplasts small, spherical, numerous.
Southern Ocean, south of Australia; North Atlantic Ocean (Hasle & Syvertsen, 1997).
This appears to be the first record of this species from southern waters.