Aulacoseira pusilla (Meister) Tuji & Houki,

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 : 3

Aulacoseira pusilla (Meister) Tuji & Houki,

Bull. Natl. Sci. Mus, Ser. B (Botany), 30: 38, fig. 161. 2004.

( Figs. 17, 18 )

Valves cylindrical. The cells form short chains linked by small marginal spines. Rows of pervalvar areolae are curved to the right (dextrorse). Rounded areolae. Sulcus slightly pronounced. The ratio of the mantle height to valve diameter is usually close to or slightly less than one μm. Mantle height: 2.5-3.0 μm, diameter: 5.0-5.5 μm, striae: 17.3-20.1 in 10 μm. The specimens were consistent and identified according to Brazilian studies Bertolli et al. (2010), Bicudo et al. (2016), and Cavalcante et al. (2013). A. pusilla differs from other species due to the short chains, presence of curved striae (dextrorse), and delicate areola ( Bicudo et al. 2016).

Material examined: BRAZIL, MATO GROSSO DO SUL: Taquaruçú, Patos Lake , 23.III.2018, sediment, D.T. Ruwer (Nupélia UEM 18098-103 , 18106 ).

Occurrence: first citation for Upper Paraná River floodplain.

Figures

Figure 2-40. Sediment diatoms from subtropical floodplain lakes (LM). 2-3. Discostella stelligera; 4-6. Aulacoseira ambigua; 7-9. Aulacoseira distans; 10-11. Aulacoseira granulata; 12-13. Aulacoseira italica; 14-16. Aulacoseira herzogii; 17-18. Aulacoseira pusilla; 19-23. Fragilariforma brasiliensis; 24-27. Pseudostaurosira cf. brevistriata; 28-31. Staurosira sp.1; 32-37; Staurosirella sp.1; 38-40. Staurosirella crassa. (Scale bar:10 μm).