Plagiotropis lepidoptera (Gregory) Kuntze

Division: Chromophyta
Class: Bacillariophyceae
Order: Bacillariales
Suborder: Bacillariineae
Family: Naviculaceae Kützing
Genus: Plagiotropis Pfitzer emend Paddock
Scientific name: Plagiotropis lepidoptera (Gregory) Kuntze

Valves similar to those of Navicula, but very convex. Lanceolate, acute, usually with a wing or longitudinal band on one or both sides. Median line straight, not sigmoid, on a central or excentric keel; raphe at edge of keel. Axial area is not evident. Central area small, sometimes transverse. Striae transverse and longitudinal, punctuate; girdle zone simple. Chromatophores are either two or four plates, serrated or indented. Pyrenoids are present. Chromatophores on the girdle band as in most naviculoid diatoms (Cupp, 1943).

Synonyms:
Tropidoneis lepidoptera (Gregory) Cleve; Amphiprora lepidoptera Gregory

 

References:
Cupp, 1943: p. 197, Fig. 149 (as Tropidoneis lepidoptera); Hendey, 1964: p. 256, Pl. XXXVI: 2, 4 (as Tropidoneis lepidoptera); Hendey, 1970: p. 149 (as Tropidoneis lepidoptera); Ricard, 1987: p. 253, Figs. 843-851; Witkowski et al., 2000: p.338, Pl. 174: 1, 2.

Description:
Cells rectangular, linear-oblong, constricted in the middle. Valves lanceolate, acute or apiculate; central area small or transversely lanceolate. Wing is unilateral, projecting above the central nodule. Striae transverse; length of valves 200-350 μm (Cupp, 1943).

Dimensions:
Cells length 180-220 µm; width 30-32 µm; transapical striae 20-21 in 10 µm.

Distribution:
Littoral species, but reported occasionally in the plankton.

Sites of occurrence in RSA:
In Winter 2006 Cruise, this species was observed at various sites (refer sites map), although never in large numbers; maximum abundance (4.3*10^2 cells/l) was associated with the Strait of Hormuz (St. 14a). It has been previously reported (as Tropidoneis lepidoptera) from Kuwaiti shore (Hendey, 1970) and coastal waters (Al-Kandari et al., 2009).