Manguin (1957: 118, pl. 3, fig. 16a–f)
Manguin (1960: 274, pl. 7, figs 83–88), Priddle & Fryxell (1985: 20, figs on p. 21)
Cells chain-forming, heavily silicified, rectangular in girdle view; pervalvar axis 42–48 µm. Valves oval-elliptical; apical axis 37–43 µm, depressed in the centre and with a small central spine. Apertures between cells small. Setae long, coarse, orientated almost perpendicular to pervalvar axis, spinose; in valve view, one seta ±continues in the direction of the (longer) apical axis, while the other curves away from it (Manguin, 1957: fig. 16c).
Southern Ocean, south of Australia; Terre Adélie (Manguin, 1957, 1960).