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Authority

Cleve (1896: 12, pl. 2, figs 14–16)

Class

Diatomophyceae

Order

Centrales

Family

Thalassiosiraceae

Synonyms

Thalassiosira tcherniai Manguin (1957: 115, figs 9, 51)

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Basionym

N/A

Additional References

Hendey (1937: 239, pl. 11, fig. 10), Hasle & Heimdal (1968: fig. 23), Newell & Newell (1977: 170), Johansen & Fryxell (1985: 170, figs 27, 43), Hasle & Syvertsen (1990a: 87, pl. 11.5, fig. 4), Moisan & Fryxell (1993: 293), Hasle & Syvertsen (1997: 68–70, pl. 8)

Description

Cells chain-forming, with chitinous strands from central processes connecting the cells, sometimes in mucilaginous colonies, discoid, rectangular in girdle view; pervalvar axis 6–15.8 µm (8–25 µm fide Hendey, 1937). Valves circular, flat, 17–62 µm diameter. Areolation radial; areolae 16–20 in 10 µm, hexagonal, with finger-like projections (Fig. c, d). Strutted processes numerous (c. 7) in valve centre and scattered over valve face and mantle (Fig. e) (5–10 in 10 µm; Hasle & Syvertsen, 1997); processes operculate, with external extensions. Labiate process solitary, large, marginal (Fig. b).

Distribution

Coastal waters off Davis Station, East Antarctica and Drygalski Glacier, Ross Sea; Antarctic sectors of the Indian and Pacific Oceans (Johansen & Fryxell, 1985); Weddell-Scotia Confluence (Garrison et al., 1987).

Comments

Syvertsen (1977) noted that T. gravida is not known to form resting spores, unlike other closely related species.

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