Family: Naviculaceae Kützing
Genus: Trachyneis Cleve
Scientific name: Trachyneis debyi (Leudiger-Fortmorel) Cleve
Alloineis debyi Leudiger-Fortmorel; Trachyneis debyi var. osculifera Cleve;non Trachyneis debyi sensu Cleve, 1894
Hendey, 1970: p. 149; Simonsen, 1974: p. 43, Pl. 27, 28: 1 .
Valves lanceolate; axial area narrow; raphe straight; central area rounded, not reaching the valve margin. Valve surface areolate, complex. Alveoli oblique, radiate. Chromatophores: two elongated plates, lying along the girdle.
Cells length 180-210 µm; width 22-25 µm.
Mainly littoral tropical/subtropical species, but is frequently found in the plankton.
Sites of occurrence in RSA:
In Winter 2006 Cruise, it was present in small numbers at scattered stations only in the inner RSA (refer sites map). It has been previously reported from the inner RSA (Simonsen, 1974) and from Kuwaiti shore (Hendey, 1970).