Biddulphia sinensis Greville
Hustedt, 1930: p. 839, Fig. 493 (as Biddulphia sinensis); Allen and Cupp, 1935: p. 146, Fig. 81 (as Biddulphia sinensis); Hendey, 1964: p. 105, Pl. XX: 1 (as Biddulphia sinensis); Simonsen, 1974: p. 27; Throndsen et al., 2007: p. 176.
Cells solitary or united by their spines to form loosely connected colonies. In girdle view, the frustule is shaped not unlike a pillow, being about 2-2.5 times as long as it is broad. Weakly siliceous. Valves elliptical, having apices furnished with short processes; valve surface slightly concave, bearing two spines which originate close to the base of the processes. Spines long, equal to or a little longer than the apical length of the valve (i.e., the width of the frustule when lying in girdle view). Chromatophores: numerous small irregular bodies scattered throughout the cell. Apical axis of valve 120-260 µm; transapical axis of valve 60-80 µm; length of cell up to 300 µm (Hendey, 1964).
Cells length 95-180 µm; width 80-150 µm.
Truly planktonic species, widely spread in temperate and warm waters.
Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred at different sites (refer sites map), usually in small numbers; maximum abundance (4.9*10^2 cells/l) was recorded in the Sea of Oman (St. 98). It has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti waters of the inner RSA (Al-Yamani et al., 2004; Al-Kandari et al., 2009).