(van Heurck) Hust. (Hustedt, 1958: 160, pl. 11, figs 140–144; pl. 12, fig. 159)
Fragilariopsis linearis var. curta (van Heurck) Freng., in Frenguelli & Orlando (1958: 107, pl. 4, fig. 31)Nitzschia curta (van Heurck) Hasle (1972a: 115), Buck & Garrison (1983: 1264, fig. 8), Everitt & Thomas (1986: 9, fig. 2E), Fryxell (1989: 12)See Hasle (1965b) for full synonymy, LM and EM descriptions, discussion of nomenclatural problems and distribution.
Fragilaria curta van Heurck (1909: 24, pl. 3, fig. 37)
Hendey (1937: 330, as Fragilaria curta), Hasle (1965b: 32, pl. 6, fig. 6; pl. 12, figs 2–5; pl. 13, figs 1–6; pl. 16, fig. 6; pl. 17, fig. 5), Hasle & Medlin (1990c: 181, pl. 24.6, figs 2–5), Moisan & Fryxell (1993: 493)
Cells solitary or chain-forming, attached by the valve surfaces, ±linear in valve view, with rounded poles, one broader than the other; apical axis 10–42 µm; transapical axis 3.5–6 µm. Transapical striae 9–12 in 10 µm, straight, but striae near valve poles curved. Interstrial membranes perforated by (1–) 2 (–3) rows of areolae, c. 30 in 10 µm. Fibulae present in slightly lower numbers than striae, comparatively broad and irregularly placed. Pseudonodulus absent. Terminal nodules not confirmed (Hasle, 1965b).
Drygalski Glacier, Ross Sea; type locality, dark greenish brown sea-ice, 65°15.5’S, 64°30.0’W; KERFIX, 50°40’S 68°25’E, Southern Ocean (Kopczyńska et al., 1998); sea-ice near Davis Station (Archer et al., 1996b); BRATEGG samples from the Antarctic (Hasle, 1965b); 74°40’–77°37’S (Cassie, 1963); Antarctic ice-edge to the mid-tropical zone of the South Atlantic, but most commonly observed in the Antarctic (Hustedt, 1958); Weddell-Scotia Confluence (Garrison et al., 1987); coastal waters off Syowa Station, East Antarctica (Ishikawa et al., 2001).
Hendey (1937) described this species as being characteristic of the coastal diatom flora of land masses within the Polar Front. Manguin (1960) observed F. curta at all sampling stations within the Antarctic zone and in greatest numbers near the coast, as did Kozlova (1962). Due to its size range and general shape, F. curta is easily confused with F. cylindrus; the former is slightly heteropolar and with striae 9–12 in 10 µm, whereas F. cylindrus is isopolar (linear) with striae 13–17 in 10 µm.