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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)

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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.

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