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Authority

Manguin (1957: 131, pl. 6, fig. 43a–c)

Class

Diatomophyceae

Order

Pennales

Family

Bacillariaceae

Synonyms

Nitzschia pacifica Cupp (1943: 204, fig. 157), Hustedt (1958: 177, pl. 13, figs 193, 194)
Nitzschia heimii (Manguin) Hasle (1965a: 21, pl. 1, figs 6, 7; pl. 10, figs 9–13; pl. 11, figs 1–7), Hasle & Medlin (1990a: 169, pl. 22.2, figs 9–13)

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Basionym

N/A

Additional References

Manguin (1960: 332, pl. 19, figs 223, 224), Hasle & Syvertsen (1997: 315, pl. 70, tab. 74)

Description

Cells solitary or in long rigid chains with c. a quarter of cell ends overlapping, linear to lanceolate and attenuated towards the poles in valve view, with one margin straight; cell ends somewhat sigmoidal and obliquely truncated at the poles in girdle view; apical axis 67–120 µm; transapical axis 4–6.5 µm. Transapical striae broad, usually strongly silicified, 19–26 in 10 µm. Interstrial membranes perforated by 1 or 2 rows of minute poroids, c. 50–80 in 10 µm; poroids in 2 or 3 rows on valve mantle and valvocopulae. Raphe keel eccentric; fibulae distinct, 11–16 in 10 µm. Central nodule present.

Distribution

Southern Ocean, south of Australia; Heard I.; type locality, coastal Terre Adélie (Manguin, 1957); Antarctic and sub-Antarctic (Hasle & Medlin, 1990a); North Atlantic (Hasle, 1965a); KERFIX, 50°40’S 68°25’E, Southern Ocean (Kopczyńska et al., 1998); Weddell-Scotia Confluence (Garrison et al., 1987).

Comments

Specimens from the most northerly sub-Antarctic stations (Hasle, 1965a) had 70–80 small poroids in 10 µm and rather broad intervals between the transapical rows of poroids.

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