Eunotia rabenhorstii var. monodon Cleve & Grunow

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 : 7-10

Eunotia rabenhorstii var. monodon Cleve & Grunow

in Van Heurck, Syn. Diat. Belg., pl. XXXV, fig. 12B. 1881.

( Figs. 76, 77 )

Valves with dorsal margin convex with an attenuatedrounded undulation in the middle region, ventral margin concave. Ends rounded, widely dilated. Striae parallel to radiate towards the ends. Length: 9.0-25.5 μm; width: 5-9 μm; striae 13-16 in 10 μm. E. rabenhorstii var. monodon resembles E. rabenhorstii var. triodon Cleve & Grunow , differ by the number of undulations on the dorsal margin. E. rabenhorstii var. monodon presents one undulation while E. rabenhorstii var. triodon has three undulations on the dorsal margin ( Van Heurck 1881). The specimens observed are similar to those registered by Costa et al. (2017).

Material examined: BRAZIL, MATO GROSSO DO SUL: Taquaruçú, Patos Lake , 23.III.2018, sediment, D.T. Ruwer (Nupélia UEM - 18098 , 18101-102 , 18104 , 18106-107 , 18109-111 , 18113-121 .

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).