Eunotia cf. bidens Ehrenberg,

Ruwer, Daiane Trevisan & Rodrigues, Liliana, 2021, Sediment diatoms from Upper Paraná River floodplAiN lAKeS: New recordS, Iheringia, Série Botânica (e 2021012) 76, pp. 1-16 : 7

Eunotia cf. bidens Ehrenberg,

Ber. K. Akad. Wiss. Berlin, 1841: 413. 1843.

( Figs. 69-71 )

Valves with dorsal margin convex with two slightly prominent undulations, ventral margin slightly concave. Ends truncated, detached from the valve body. Striae parallel to radiate. Length: 33-76 μm; width: 10-13 μm; striae 10-14 in 10 μm. The population observed are consistent concerning some valve morphology features and dimensions with Eunotia bidens presented in Metzeltin & Lange-Bertalot (1998) and Metzeltin et al. (2005). However, the studied population was maintained as a conferatur due to variation in the morphology of the ends. E. bidens has subcapitate, obtusely rounded apices, and slightly detached.

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

Occurrence: first citation for Upper Paraná River floodplain.

Figures

Figure 66-85. Sediment diatoms from subtropical floodplain lakes (LM). 66-68. Eunotia cf. neomundana; 69-71. Eunotia cf. bidens; 72-73. Eunotia papilio; 74-75. Eunotia pseudosudetica; 76-77. Eunotia rabenhortii var. monodon; 78-82. Eunotia sp. 1; 83-85. Eunotia sp. 2. (Scale bar: 10 μm).