Naviculadicta sp. 1

(Figs. 140-152)

Valves elliptical or linear-lanceolate with rounded ends. Axial area narrow and linear. Central area rectangular limited by a shortened striae, asymmetrical, wider in larger individuals. Raphe filiform. Striae parallel to slightly radiate toward the central area. Length: 8-16 μm; width: 4.0-5.5 μm; striae 16-20 in 10 μm. The specimens observed are morphologically similar to Naviculadicta sp. 1 from Metzeltin & Lange-Bertalot (2007). Besides that, Naviculadicta sp. 1 from Metzeltin & Lange-Bertalot (2007) differ by the central area wider and symmetric. The population from this study resemble Sellaphora saugerresii (Desmazières) Wetzel & Mann and Navicula minima Grunow registered by Wetzel et al. (2015), however; Naviculadicta sp. 1 differs concerning central area shape and striae density.

Material examined: BRAZIL, MATO GROSSO DO SUL: Batayporã, Garças Lake, 21.IX.2017, sediment, D.T. Ruwer (Nupélia UEM - 18073, 18085-97) .