Navicula sp. 2

Al-Handal, Adil Y., Compère, Pierre & Criobe-Usr, Catherine Riaux-Gobin, 2016, Marine benthic diatoms in the coral reefs of Reunion and Rodrigues Islands, West Indian Ocean, Micronesica 2016 (3), pp. 1-78 : 29

Navicula sp. 2 (Pl. 13, Fig. 9)

Features: Valves elliptic to broadly lanceolate with protracted subrostrate ends, 10-13 µm, 6-7 µm wide. Axial area narrow, linear. Central area rectangular, with one shortened stria bordering the central area. Raphe branches straight with distinct central raphe endings, slightly deflected to the same direction. Distal raphe endings terminate at apices and deflected to the same direction. Apices with two distinct areolae. Transapical striae moderately radiate in mid-valve becoming convergent at the ends, 20-22 in 10 pm. Striae composed of 4-5 distinctly elongated areolae.

Remarks: A population of a rather small-sized Navicula also appeared in the SEM material from the Mascraenes but identification was difficult due to rarity of the specimens.

Occurrence: Rare in Reunion Island.

Olifantiella mascarenica Riaux-Gobin et Compère (Pl. 14, Fig. 1 ) References: Riaux-Gobin & Compère 2009, p. 180, figs (LM) 1-5, figs (SEM) 6-22.

Features: Apical axis: 6.7- 8.2 µm long, 1.8-3.4 µm wide, striae 37-41 in 10 µm. Valves small, linear lanceolate with capitate apices, very slightly constricted in mid-valve. Raphe straight, filiformm, axial area very narrow, proximal raphe endings close to each other, small, simply inflated, terminal raphe endings small, slightly deflected. Striae parallel throughout and not reaching the valve margin.

Remarks: This species is so far only recorded from marine lagoons in Reunion Island.

Occurrence: Frequent in Reunion Island.

Figures

Figure 1. Map showing location of Reunion and Rodrigues Islands, Indian Ocean and sampling sites.