Eunotia papilio (Ehrenberg) Grunow,

Alg. Novara, 94. 1868.

(Figs. 72-73)

Valves with dorsal margin convex with two prominent undulations, ventral margin tightly concave. Ends cuneate, dorsally deflected. Striae parallel to radiate towards the ends. Length: 25-35 μm; width: 7-12 μm; striae 8-10 in 10 μm. The population observed is consistent with specimens from Metzeltin et al. (2005) and Brazilian studies of Costa et al. (2017) and Oliveira et al. (2012). This taxon differs from other Eunotia species by the presence of two prominent undulations on the dorsal margin and cuneate ends.

Material examined: BRAZIL, MATO GROSSO DO SUL: Taquaruçú, Patos Lake, 23.III.2018, sediment, D.T. Ruwer (Nupélia UEM - 18098-18099, 18101-122) .

Occurrence: first citation for Upper Paraná River floodplain.