Asteromphalus heptactis Ralfs

Division: Chromophyta
Class: Bacillariophyceae
Order: Biddulphiales
Suborder: Coscinodiscineae
Family: Asterolampraceae Smith
Genus: Asteromphalus Ehrenberg
Scientific name: Asteromphalus heptactis (Brébisson) Ralfs

 

Species: heptactis

Synonym:
Spantangidium heptactis Brébisson

References:
Hustedt, 1930: p. 494, Fig. 277; Cupp, 1943: p. 69, Fig. 32; Hendey, 1964: p. 96, Pl. XXIV:5; Hendey, 1970: p. 115; Simonsen, 1974: p. 25; Priddle and Fryxell, 1985: p. 116-117 (A,E); Ricard, 1987: p. 151, Figs. 54-57.

Description:
Usually seven rays of unequal length, the narrow ray somewhat longer than the others.Central field slightly eccentric, one-fourth to one-third, the diameter of cell. Diameter of cells 38-100 µm. Areolae rather large, 6 or 6½ in 10 µm (Cupp, 1943).

Dimensions:
Longer diameter 40-43 µm; shorter diameter 35-38 µm.

Distribution:
Oceanic, temperate species.

Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred in very small numbers at scattered sites (refer sites map); maximum abundance (32 cells/l) was associated with the southern part of the inner RSA (St. 77). Species has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti shore (Hendey, 1970) and coastal waters (Al-Yamani et al., 2004).