Cosc. wailesii Gran et Angst

Division: Chromophyta
Class: Bacillariophyceae
Order: Biddulphiales
Suborder: Coscinodiscineae
Family: Coscinodiscaceae Kützing
Genus: Coscinodiscus Ehrenberg
Scientific name: Coscinodiscus wailesii Gran et Angst

 

Species: wailesii

References:
Cupp, 1943: p. 59, Fig. 23;Throndsen et al., 2007: p. 151.

Description:
Cells cylindrical with concave ends,large, 230-350 µm in diameter.Mantle cylindrical, 44-70 µm high.Center of valve hyaline with irregular outline and free areolae. Areolae about 6 in 10 µm, slightly increasing in size from central area outward, farther out decreasing. Outer membrane delicately poroid. Marginal spines not visible in valve view, 3-5 µm from edge of mantle, 10-12 µm apart. Distinct hyaline lines radiate inward. Areolae of same size at both sides of spinulae, 6 in 10 µm. Intercalary bands two at each valve, first one broader than the second (Cupp, 1943).

Harmful Effect:
Non-toxic bloom-forming species. In the late 1970 the fishermen in the Plymouth area complained that their nets became logged with a heavy jelly-like material. Mucilage produced in cultures of Coscinodiscus wailesii, is an important constituent of the phytoplankton in these waters from 1977, and mucilage from the nets were shown to have basically the same chemical structure (Boalch, 1984).

Dimensions:
Valve diameter 250-320 µm.

Distribution:
Oceanic and neritic cosmopolitan species.

Sites of occurrence in RSA:
In Winter 2006 Cruise, this species occurred at various stations in very small numbers (refer sites map). It has been previously reported from the inner RSA (Kuwaiti waters) (Al-Kandari et al., 2009).