Family: Naviculaceae Kützing
Genus: Petroneis Stickle et Mann ex Round et al.
Scientific name: Petroneis granulata (Bailey) Mann ex Round et al.
Navicula granulata Bailey; Navicula polysticta Greville; Navicula brasiliensis Grunow;Navicula baileyana Schmidt; Navicula javanesis Leudiger-Fortmorel.
Hendey, 1964: p. 208, Pl. XXXI: 6 (as Navicula granulata); Hendey, 1970: p. 133 (as Navicula granulata); Ricard, 1987: p. 239, Fig. 726 (as Navicula granulata); Witkowski et al., 2000: p. 327, Pl. 97: 1, 2.
Valves elliptic-lanceolate with obtusely rounded rarely slightly rostrate apicas, 40-160 µm long, 22-55 µm broad. Raphe straight, extremely central endings expanded, apical endings hooked to one side, axial area narrow, between valve center and apices slightly widened; central area small, irregularly circular to transverse expanded. Transapical striae coarsely punctate; radiate throughout, 8-12 in 10 µm; puncta along the valve margin, distinctly more dense than in the middle (Witkowski et al., 2000).
Cells length 104 µm; width 35 µm; transapical striae 11 in 10 µm.
Mainly littoral species, but is frequently found in the plankton.
Sites of occurrence in RSA:
In Winter 2006 Cruise, it was found in small numbers at one locality (St. 10a) in the northwestern part of the inner RSA (refer site map). Species has been previously reported (as Navicula granulata) from Kuwaiti shore (Hendey, 1970).