H.A.Thomsen (1982: 20, figs 51, 52 (holotype), 53–58, 60, 63)
Marchant & Perrin (1986: 209, fig. 5)
Cells solitary or in sphaerical colonies. Lorica bell-shaped, 22–30 µm long, to 18 µm diameter; longitudinal costae 13–15; transverse costae 3. Longitudinal costae comprising 9 or 10 costal strips; anterior costal strips thinner than those of the rest of the lorica. Number of costal strips in each transverse costa equal to the number of longitudinal costae. Arrangement of costal strips at the base of the lorica complex often appearing stellate. Intact protoplasts not found in Prydz Bay material.
Burton Lake, a coastal lagoon in the Vestfold Hills, Prydz Bay, East Antarctica (Marchant & Perrin, 1986); Disko Bay, West Greenland (Thomsen, 1982).
Although the Prydz Bay cells were solitary, Thomsen (1982) reported that cells in West Greenland samples were “commonly united into sphaerical colonies (hence the specific epithet) with the lorica apertures pointing towards a common cavity. Cells in the colonies are arranged in clusters of six, and neighbouring cells are united along adjoining longitudinal costae between the two anterior transverse costae”. Thomsen also described protoplast dimensions of c. 7 × 4 µm.