K.R.Buck & H.J.Marchant, in Buck et al. (1990: 392, figs 1, 2, 3 (holotype), 4–10)
Cells solitary. Lorica barrel-shaped and tapering towards the posterior end, to 20–22 µm long, 13–18 µm diameter; oral diameter 4.8 µm; longitudinal costae c. 20; transverse costae 12; pedicel absent. Longitudinal and transverse costal strips c. 5 µm long, curved, all with simple ends except those at the distal ends of posterior longitudinal costal strips which are dilated at their junctions. Longitudinal costae to the outside of transverse costae. Anterior transverse costae spirally arranged; posterior transverse costal strips greater in diameter than those at anterior end of lorica. Protoplast spherical, c. 6 µm diameter, supported by a solid suspensory membrane attached to posterior end of lorica; collar of tentacles 4.5 µm long. Flagellum 24 µm long (including a 5 µm long hairpoint), arising from anterior end of protoplast.
Sea-ice near Davis Station, East Antarctica; Weddell Sea, in the sea-ice (Buck et al., 1990).
The most conspicuous component of the lorica of this choanoflagellate, particularly if the protoplast is absent, is the membranous sheath that supports the cell. This membrane has a central hole and appears to be attached directly to the lorica at points along its anterior margin and at its posterior apex.