Family: Coscinodiscaceae Kützing
Genus: Coscinodiscus Ehrenberg
Scientific name: Coscinodiscus asteromphalus Ehrenberg
Coscinodiscus asteromphalus var.conspicua Grunow ex van Heurck.
Hustedt, 1930: p. 452, Fig. 250; Allen and Cupp, 1935: p. 118, Fig. 14; Hendey,1964: p. 78, Pl. XXIV: 2; Hendey, 1970: p.
111; Simonsen, 1974: p. 14; Priddle and Fryxell, 1985: p. 128-129.
Cells discoid, large, solitary. Valves slightly convex. Valve surface covered with a strong areolation, having a large central rosette enclosing a small structureless area. Areolae polygonal; outside the central rosette for a short distance along the radius, the areolae are somewhat small, gradually becoming larger, until at distance equal to half the radius , they attain their maximum size, after which they again decrease. Areolae furnished with characteristic secondary and tertiary structure. Chromatophores: numerous large rounded plates. Diameter of valve 230-360 (mostly 330) µm (Hendey, 1964).
Valve diameter 280-320 µm.
Pelagic plankton species with a worldwide distribution.
Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred at different sites (refer sites map) in very small numbers; maximum abundance (35 cells/l) was associated with the Iranian coast in the central part of the inner RSA (St. 56). It has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti shore (Hendey, 1970) and coastal waters (Al-Kandari etal., 2009).