Actinocyclus octonarius Ehrenberg

Division: Chromophyta
Class: Bacillariophyceae
Order: Biddulphiales
Suborder: Coscinodiscineae
Family: Hemidiscaceae Hendey
Genus: Actinocyclus Ehrenberg
Scientific name: Actinocyclus octonarius Ehrenberg

Species: octonarius

Synonym:
Actinocyclus ehrenbergii Ralfs

References:
Pavillard, 1925: p. 20, Fig. 30 (as Actinocyclus ehrenbergii); Hustedt, 1930: p. 525, Figs. 298,299, 301 (as Actinocyclus ehrenbergii); Hendey, 1964: p. 83-84, Pl. XXIV: 3, 4; Hendey, 1970:p. 113; Simonsen, 1974: p. 21; Priddle and Fryxell, 1985: p. 108-109; Ricard, 1987: p. 149,Figs. 35-39; Witkowski et al., 2000: p. 21, Pl. 4: 2, 3; Throndsen et al., 2007: p. 147.

Description:
Each areola row parallel to the central row of the sectors. Labiate processes at the end of side rows. Broad marginal zone with
areolae, smaller than elsewhere on the valve face. Processes and pseudonodulus are readily seen with LM. Diameter 50-300 µm; 6-8 areolae in 10 µm; 8-11 µm between marginal processes (Throndsen et al., 2007).

Dimensions:
Valve diameter 60-75 µm.

Distribution:
Common species in neritic plankton, cosmopolitan.

Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred in small numbers at scattered sites (refer sites map). It has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti shore (Hendey, 1970) and coastal waters (Al-Kandari et al., 2009).