G.A.Fryxell & Hasle (1972: 312, figs 37–46)
Cells discoid; pervalvar axis c. 18–20 µm. Valves flat, rounded at the margins, circular, 30–88 µm diameter. Areolation eccentric, finer on valve mantle than on valve face (Fig. e); areolae (3–) 5–7 in 10 µm in the centre, (5–) 6–8 in 10 µm near the margin, with internal cribra (Fig. b). Single central areola somewhat larger, surrounded by an inconspicuous rosette of 7 areolae, in contrast to hexagonal pattern on remainder of the valve. Strutted processes scattered over valve face, as well as in single marginal ring, 4–6 in 10 µm, each with a short spine-like external extension (Fig. b, f), and a short internal extension (Fig. d); strutted processes with 5 satellite pores at their base (Fig. d). Two labiate processes on valve margin, c. 160–170° apart, internally slit-like (Fig. d), externally with a very long extension (Fig. e, f).
Prydz Bay, East Antarctica; type locality, 54°41’S 150°12’E, O.R.S. “Eltanin ” Cruise 38, Station 10a, Southern Ocean, south of Australia (Fryxell & Hasle, 1972); Pacific and Indian Oceans and Gulf of Mexico (Fryxell & Hasle, 1972).