W.N.Ellis (1929: 74, fig. 10)
Thomsen (1982: 6, figs 7, 8), Anderson (1988: 37)
Cells solitary. Lorica 27–30 µm long, to 20 µm at posterior end. Longitudinal costae 12, each comprising 7 costal strips, the 2 anteriormost strips extending 9–10 µm beyond the anterior transverse costa. Transverse costae 4; anterior transverse costa composed of a double row of costal strips. Protoplast ellipsoidal, c. 5 µm long, suspended centrally in the lorica chamber, supporting a collar of c. 6 µm long tentacles extending almost to the level of the anterior transverse costa.
Inshore areas of Prydz Bay, East Antarctica (Marchant, 1985b); Greenland (Thomsen, 1982); northern Pacific (Norris, 1965).
When present in high numbers, suspension feeders such as Diaphanoeca grandis and other choanoflagellates may play a significant role in marine food webs. Ingestion experiments on D. grandis have shown that cells can ingest particles in the size range of 0.063–1.0 µm diameter and fluorescently labelled dextrans with a molecular weight of 4,000–2,000,000 (Marchant & Scott, 1992), suggesting they are capable of exploiting a wide range of food sources.