Eunotia papilio (Ehrenberg) Grunow 1868

Ruwer, Daiane Trevisan, Blanco, Saúl & Rodrigues, Liliana, 2021, Eunotia Ehrenberg (Eunotiaceae, Bacillariophyta) in a subtropical floodplain: a new species and taxonomic contributions, Phytotaxa 505 (2), pp. 157-175 : 165

Eunotia papilio (Ehrenberg) Grunow 1868 , 94 ( Figs 51–57 )

Valves dorsiventral, with butterfly-like shape. Ventral margin concave and dorsal margins convex with two undulations. Valve apices cuneate gradually narrowed. Valve length 25–35 μm (measured at the middle), valve width 7–12 μm, 12.4–15.7 μm width in the central swelling. Areolae slightly distinguishable in LM. Transapical striae unevenly spaced 8–10 striae in 10 μm, curved-radiated, slightly denser at the apices, interrupted close to the ventral margin. Striae composed of non-continuous rows of rounded areolae, 20–40 areolae in 10 μm (SEM).

Material examined: — BRAZIL. Mato Grosso do Sul: Taguaruçú, Patos Lake , Upper Paraná River Floodplain , sediment, 23.III.2018, Ruwer et al. ( Nupélia UEM 18098–99, 18101–22) .

Eunotia parabidens C.E.Wetzel, Costa & Lange-Bertalot in Costa et al. 2017, 42, pl. 64, figs 1, 2, pl. 65, figs 2–4, pl. 66, figs 1–4 ( Figs 58‒64 )

Valves distinctly dorsiventral, ventral margins slightly to moderately concave, dorsal margins convex with two swellings, depressed in the middle. Rectangular truncate apices, reflexed to the dorsal side, detached from the valve body. Valve length 33–76 μm (measured at the middle), valve width 10–13 μm, 11.6–14.1 μm width in the central swelling, varying from 7.1–10.2 μm width in the apices. Areolae not distinguishable in LM. Transapical striae slightly radiate, almost equidistant, presence of short striae intercalated on the dorsal margin, continue on the ventral margin. Dorsal striae spaced 10–14 in 10 μm, becoming denser at the apices, composed of continuous rows of rounded areolae, 40–50 areolae in 10 μm. Presence of a relief of transapical costae between striae. Terminal nodules close to the poles.

Material examined: — BRAZIL. Mato Grosso do Sul: Taguaruçú, Patos Lake , Upper Paraná River Floodplain , sediment, 23.III.2018, Ruwer et al. ( Nupélia UEM 18098–122) .

Figures

FIGURES 51–57. Eunotia papilio from Patos Lake sediment samples, Upper Paraná River floodplain, Brazil. 51–56. LM. 57. SEM, external view of valve. Scale bars = 10 μm.

FIGURES 58–64. Eunotia parabidens from Patos Lake sediment samples, Upper Paraná River floodplain, Brazil. 58–63. LM. 64. SEM, external view of valve. Scale bars = 10 μm.