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Authority

Hust. (Hustedt, 1958: 164, pl. 11, figs 133–136; pl. 12, fig. 153)

Class

Diatomohyceae

Order

Pennales

Family

Bacillariaceae

Synonyms

Nitzschia ritscheri (Hust.) Hasle (1972a: 115), Hasle & Medlin (1990c: 181, pl. 24.1, fig. 20; pl. 24.2, figs 1–10; pl. 24.3, fig. 8)
?Fragilaria sublinearis var. ambigua Perag. (Peragallo, 1921: 68, pl. 3, fig. 4)

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Basionym

N/A

Additional References

Hasle (1965b: 20, pl. 1, fig. 20; pl. 3, fig. 3; pl. 4, figs 1–10; pl. 5, figs 12, 13; pl. 6, fig. 1; pl. 7, fig. 8), Jousé et al. (1962: 86, pl. 6, fig. 9), Kozlova (1962: pl. 9, fig. 11)

Description

Cells solitary or in chains; small cells linear to elliptical in valve view; large cells linear to lanceolate and broader at one pole; apical axis 22–60 µm; transapical axis 8–9 µm. Transapical striae straight in the middle of the cell, curved near the valve poles; striae adjacent to broad pole more oblique than at narrow pole, 6–8 in 10 µm. Interstrial membranes perforated by 2 or 3 rows of usually alternating poroids, 18–24 in 10 µm. Fibulae curved, present in the same number as striae. Pseudonodulus absent. Canal raphe present, but not always obvious.

Distribution

Southern Ocean and coastal Antarctica, south of Australia; Southern Ocean, 57°35’S 105°46’E, offshore Wilkes Land, also 60°50’S 93°36’E, offshore Wilhelm II Land; type locality 69°43’S, 06°30’E to 61°32’S, 0°00’ (Hustedt, 1958); sub-Antarctic and Antarctic (Hustedt, 1958; Kozlova, 1962; Hasle, 1965b); Weddell-Scotia Confluence (Garrison et al., 1987); Lützow-Holm Bay (Tanimura et al., 1990).

Comments

Specimens collected by us in the Southern Ocean and coastal Antarctica, south of Australia, were of solitary cells, some being a little longer (60 µm) than previously recorded.

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