Gomphonema sp. 1

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 : 12

Gomphonema sp. 1

( Figs. 133-136)

Valves heteropolar, lanceolate, slightly linear. Apical ends cuneate, and basal ends attenuate-rounded. Axial are lanceolate, central area rectangular limited by a shortened striae. Raphe straight, with proximal ends, slightly dilated to pores. Striae short, parallel to slightly radiate toward the ends. Stigma absent. Length: 16.4 - 25 μm; width: 3.5 - 4.1 μm; striae 13 - 15 in 10 μm. The specimens observed are morphologically similar to G. rhombicum Fricke from Metzeltin et al. (2005), concerning valve shape and striae pattern. Besides that, G. rhombicum has a stigma and cuneate-rounded ends.

Material examined: BRAZIL, MATO GROSSO DO SUL: Batayporã, Garças Lake , 21.IX.2017, sediment, D. T. Ruwer (Nupélia UEM - 18068, 18072, 180086, 18090, 18093, 18095) .

Naviculales Bessey 1907

Brachysiraceae Mann 1990

Brachysira neoexilis Lange-Bertalot in H. Lange-Bertalot & G. Moser, Biblioth. Diatomol., 29: 51, pls. 5-6, 17, 32, 46, figs. 1-6, 7-11, 19-30. 1994.

( Figs. 137-139)

Valves lanceolate. Ends subcapitate. Axial area linear and narrow. Central area rounded. Raphe filiform. Striae inconspicuous, parallel to radiate, interrupted by longitudinal hyaline line. Areolae elongated, difficult to visualize in LM. Length: 22-25 μm; width: 4.5-5.0 μm. The population observed is consistent with specimens registered from Brazilian studies of Marra et al. (2016).

Material examined: BRAZIL, MATO GROSSO DO SUL: Batayporã, Garças Lake , 21.IX.2017, sediment, D. T. Ruwer (Nupélia UEM - 18066, 18071, 18076, 18083-84, 18086-87, 18093) .

Occurrence: first citation for Upper Paraná River floodplain.

Naviculaceae Kützing 1844