Eunotia sp. 1

Eunotia sp. 1

( Figs. 78-82 View Figure 66-85 )

Valves with dorsal margin convex with three slightly undulations in all cell cycle stages, ventral margin concave. Ends rounded subcapitates, slightly dorsally deflected. Striae parallel to radiate towards the ends. Length: 21.1- 56.6 μm; width: 5.0-6.8 μm; striae 11-14 in 10 μm. The specimens observed are morphologically similar to the lectotype E. tridentula Ehrenberg from Reichardt (1995), both species present three undulations on dorsal margin, however; Eunotia sp. 1 can be distinguished from this taxon by the less width valve values and by the less prominent undulations. Despite the similarity of Eunotia sp. 1 with E. tridentula registered in the Brazilian study of Faustino et al. (2016), Eunotia sp. 1 differs morphologically from E. tridentula in the Brazilian studies of Bes et al. (2012), Bicca et al. (2011), Costa et al. (2017) and Fontana & Bicudo (2012). The great morphological variability of E. tridentula , exposed mainly in the work of Metzeltin et al. (2005), emphasizes the necessity for a taxonomic revision of this group.

Material examined: BRAZIL, MATO GROSSO DO SUL: Taquaruçú, Patos Lake , 23.III.2018, sediment, D.T. Ruwer (Nupélia UEM - 18102-122 ) .