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Authority

Throndsen (1970a: 109, figs 21–25)

Class

Craspedophyceae/Choanoflagellida

Order

Choanoflagellida

Family

Acanthoecidae

Additional References

Buck & Garrison (1983: 1264, fig. 23), Thomsen et al. (1990: 380, figs 66, 67)

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Basionym

N/A

Synonyms

N/A

Description

Cells solitary. Lorica barrel-shaped, 10–14 µm long, 10–12 µm diameter; longitudinal costae 7; transverse costae 2. Longitudinal costae comprising 3 costal strips, with characteristic T-junctions where they meet the anterior transverse costa. Transverse costae comprising 7 costal strips. Protoplast obovoid, 4–6 µm long, lying in close connection with the basal part of the lorica; collar of tentacles extending to the anterior costa. Flagellum c. 20 µm long.

Distribution

Sparse at oceanic and inshore stations of Prydz Bay, East Antarctica; Weddell Sea (Buck & Garrison, 1983); North Atlantic (Throndsen, 1974); Californian coast (Thomsen et al., 1991a).

Comments

Pleurasiga minima is essentially distinguished from its close ally P. reynoldsii by the latter being conspicuously larger in size and having longitudinal costae that merge into pairs where the penultimate and ultimate longitudinal costal strips meet, resulting in only 4 longitudinal costae at the posterior end of the cell (Thomsen et al., 1990). Cells intermediate in size between the two species have also been found at oceanic sites in the vicinity of Casey Station, East Antarctica.

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