Manguin (1957: 124, pl. 5, fig. 26a–e)
Achnanthes vicentii naviculacae Manguin (1960: 308, pl. 14, figs 162a, b, 163a, b)
Everitt & Thomas (1986: 5, fig. 3D, as A. vincentii), Chalmers et al. (1996: 29, pl. 8, figs a, b)
Cells solitary, elliptical to lanceolate, heterovalvate; apical axis 6–21 µm; transapical axis 3.2–5 µm. Valves flat; upper valve with a pseudoraphe (Fig. c); lower valve with a raphe (Fig. a, b). Raphe central; terminal fissures curved in opposite directions (Fig. a). Transapical striae radiating slightly, 9–13 in 10 µm, triseriate, containing poroids. Chloroplasts 2, lying on either side of the raphe.
Renwick Glacier, Amanda Bay, East Antarctica; type locality, Cape Margérie, Terre Adélie (Manguin, 1957); epiphytic on marine macroalgae, near Davis Station, East Antarctica (Everitt & Thomas, 1986).
Chalmers et al. (1996) noted that the species name has often been written as Acnanthes vincentii. Specimens in the current study, from Prydz Bay, comprised comparatively small cells, with slightly coarser striation (9 striae in 10 µm) than described by Manguin (1957; 12–13 in 10 µm).