ABCDEFGHIJKLMNOPQRSTUVWXYZ

Authority

(van Heurck) D.G.Mann, in Round et al. (1990: 671)

Class

Diatomophyceae

Order

Pennales

Family

Diadesmidaceae

Synonyms

Navicula muticopsis f. evoluta W.West & G.S.West (1911: 283, pl. 26, figs 121–123)
Navicula muticopsis f. reducta W.West & G.S.West (1911: 284, pl. 26, fig. 124)
Navicula muticopsiformis W.West & G.S.West (1911: 284, pl. 26, fig. 131)
Navicula muticopsis f. capitata Carlson (1913: 15, pl. 1, fig. 10)
Navicula mutica var. cymbelloides Perag. (Peragallo, 1921: 16, pl. 1, fig. 28)
Navicula mutica var. truncata Perag. (Peragallo, 1921: 17, pl. 1, fig. 27)
Navicula muticopsis var. capitata Perag. (Peragallo, 1921: 17, pl. 1, fig. 40)
See VanLandingham (1975: 2687) for details of synonymy.

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Basionym

Navicula muticopsis van Heurck (1909: 12, pl. 2, fig. 181)

Additional References

Peragallo (1921: 17, pl. 1, fig. 27), Hustedt (1927–30: 614, fig. 1614), Chalmers et al. (1996: 40, pl. 12, figs e, f)

Description

Cells solitary. Valves flat, slightly capitate in valve view; apical axis 10–25 µm; transapical axis 6–10 µm; pervalvar axis 4–6 µm. Transapical striae radiating, uniseriate, 10–14 in 10 µm; areolae on the valve face rounded to slightly elongate; areolae on the mantle solitary and rounded. Single stigma present near valve centre. Raphe-sternum narrow; external central raphe endings and distal raphe endings strongly deflected in the same direction away from the stigma. Girdle bands simple, each bearing a single row of small poroids (Fig. d).

Distribution

Coastal waters near Davis Station, East Antarctica; type locality, 65°15.05’S 64°30.0’E, Station 141, “Belgica ” Expedition (van Heurck, 1909); Petermann I., Jenny I. and Léonie I., Cape Tuxen (all Antarctic Peninsula) (Peragallo, 1921); South Shetland Is. and South Orkney Is. (Håkasson & Jones, 1993).

Comments

Material collected from coastal waters off Davis Station showed all external raphe endings (central and distal) deflected in the same direction, rather than in opposite directions as was described for the genus (Mann, 1990).

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