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Authority

(Ostenf.) Hasle (1972b: 544, figs 1–10)

Class

Diatomophyceae

Order

Centrales

Family

Thalassiosiraceae

Synonyms

Thalassiosira antiqua var. septata Proschk.-Lavr. (Proschkina-Lavrenko, 1955a: 48, pl. 1, figs 12–14; pl. 2, figs 1, 2; 1955b: pl. 67, fig. 14)

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Basionym

Coscinosira oestrupii Ostenf. (Ostenfeld, 1900: 52)

Additional References

Fryxell & Hasle (1980: 805), Johansen & Fryxell (1985: 173, figs 9, 75, 76), Fryxell & Johansen (1990: 99, pl. 11.8, fig. 5), Hasle & Syvertsen (1997: 83, pl. 12)

Description

Cells chain-forming, united by chitinous threads from the off-central strutted process, discoid to rectangular in girdle view; pervalvar axis 0.5–2 times valve diameter. Valves circular, 7–60 µm diameter, flat to slightly convex. Areolation eccentric, coarse; areolae 5–10 in 10 µm in the centre, 6–12 in 10 µm nearer the margin. Strutted processes trifultate and operculate, with internal extensions (Fig. b); 1 process in an off-centre position and 1 marginal ring of processes 6–8 in 10 µm (not visible by LM). Labiate process solitary, not marginal, internally flattened and parallel to margin (Fig. b).

Distribution

Coastal waters off Davis Station, East Antarctica; cosmopolitan (Fryxell & Johansen, 1990); in broken sea-ice, Weddell Sea, Pacific and Atlantic sectors of the Southern Ocean (Fryxell & Hasle, 1980); Weddell-Scotia Confluence (Garrison et al., 1987).

Comments

N/A

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