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Authority
(R.E.Norris) Throndsen (1974: 118, fig. 45)
Class
Craspedophyceae/Choanoflagellida
Order
Choanoflagellida
Family
Acanthoecidae
Additional References
Marchant & Perrin (1986: 208, fig. 2), Marchant et al. (1987b: 15, figs 7, 8)
Basionym
Pleurasiga complexa R.E.Norris (1965: 599, fig. 21)
Synonyms
N/A
Description
Lorica somewhat waisted to form anterior and posterior chambers, 13.5–15 µm long excluding pedicel (when present); anterior chamber 8–11 µm diameter; posterior chamber 4–6.5 µm diameter; longitudinal costae 10–12; transverse costae variable, 4 or 5 in basal part of lorica. Arrangement of costal strips irregular and rather complex; longitudinal costae obliquely orientated, some of the costal strips of the posterior chamber thickened. Protoplast ovoid, to 6.5 µm long, 2.2–5 µm diameter
Distribution
Ellis Fjord, Vestfold Hills, East Antarctica (Marchant & Perrin, 1986); North Atlantic (Throndsen, 1974); north-east Pacific (Norris, 1965).
Comments
This species is readily recognised by its waisted outline and the obliquely orientated costae. Clusters of Stephanoeca complexa cells are sometimes found associated with other organisms, especially flagellates.