* Fragilaria spectra P.D.Almeida, E.Morales & C.E.Wetzel (2016: 174)

Figs 3: AP–AR

Length: 42.7–70.1 µm; width: 1.8–3.1 µm; striae: 19–24 in 10 µm (n = 12)

Taxonomical remarks: the individuals found in our samples presented greater width (1.8–3.1 × 1.5–2.5 µm) and lower striae density (19–24 × 24–25 in 10 µm) in comparison to the original description (Almeida et al. 2016), however, the delicate appearance of the valves is similar. In our samples, Fragilaria tenera (Smith) Lange-Bertalot (1980: 746) was distinguished by lower striae density (15–16 in 10 µm) and Fragilaria tenera var. nanana by the capitate apices (Lange-Bertalot & Ulrich 2014, Almeida et al. 2016).