Family: Chaetocerotaceae Ralfs in Pritchard
Genus: Chaetoceros Ehrenberg
Scientific name: Chaetoceros eibenii Grunow
Cupp, 1943: p. 106, Fig. 61; Hendey,1964: p. 121, Pl. XVII: 5.
Cells cylindrical, broadly elliptical in valve view; chains straight, not twisted, 25-50 µm broad. Apertures rather flat, hexagonal. Valve surface flat; mantle moderately low, one-third the length of cell or less with shallow constriction at suture with girdle. Valves with minute, hardly visible spine in center; setae arising from near corner of cell, crossing each other very near bases, curved outward from apical plane, half of them nearly parallel to transapical axis. Setae armed with minute spines, farther out with fine striations, 20-22 in 10 µm, hexagonal in cross section (Cupp, 1943).
Apical axis 30-33 µm; pervalvar axis 24-27 µm.
Neritic, tropical and temperate species.
Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred at different sites (refer sites map), usually in small numbers; however, it was quite abundant at some localities; maximum abundance (1.3*10^4 cells/l) was associated with the Sea of Oman (St. 88).