Family: Rhizosoleniaceae De Toni
Genus: Rhizosolenia (Ehrenberg) Brightwell
Scientific name: Rhizosolenia setigera Brightwell
Rhizosolenia japonica Castracane; Rhizosolenia hensenii Schütt
Pavillard, 1925: p. 32, Fig. 48; Hustedt, 1930: p. 589, Fig. 336; Allen and Cupp, 1935: p. 128, Fig. 37; Cupp, 1943: p. 88, Fig. 49; Crosby and Wood, 1958: p. 523, Pl. 39: 76; Hendey, 1964: p. 149, Pl. IV: 1; Simonsen, 1974: p.29; Ricard, 1987: p. 173, Fig. 226; Throndsen et al., 2007: p. 161.
Cells rodlike, cylindrical. Diameter 4-20 µm. Valves conical, only slightly oblique. Apical process cylindrical, thickened for some distance from base,solid at base or with a very fine canal in the center, with a very long, fine,straight spine. Intercalary bands scale-like, two long bands pointing toward apex. Cell wall thin, weakly siliceous, without distinct or visible structure.Chromatophores numerous, small, elliptical (Cupp, 1943).
Cells length 300-350 µm; diameter 16-19 µm.
Neritic, north temperate species (Cupp, 1943).
Sites of occurrence in RSA:
In Winter 2006 Cruise, this species was frequently observed at various sites (refer sites map),although never in large numbers; maximum abundance (8*10^2 cells/l) was associated with the Iranian coast in the Sea of Oman (St. 88). It has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti waters (Al-Yamani et al., 2004; Al-Kandari et al.,2009).