Eunotia monodon Ehrenberg 1841

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 : 163-164

Eunotia monodon Ehrenberg 1841 , 143 ( Figs 37–44 )

Valves dorsiventral, arched with parallel ventral and slight convex dorsal margins. Apices rounded, subcapitate. Valve length 25.2–76.1 μm, valve width 6–10 μm (measured at the center). Areolae easy to discern in LM. Transapical striae parallel to slightly radiate, evenly or unevenly spaced, 8–13 striae in 10 μm, slightly denser at the apices. Striae composed of continuous rows of elliptical areolae, 30–40 areolae in 10 μm (SEM). Terminal nodules close to the poles, terminal raphe fissures long, extends over almost the entire apical end.

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); Batayporã, Garças lake , Upper Paraná River Floodplain , sediment, 19.IV.2017, Ruwer et al. ( Nupélia UEM 18066, 18072–73, 18075–76, 18086, 18090, 18094) .

Eunotia neomundana Metzeltin & Lange-Bertalot in Lange-Bertalot 1998, 5: 69, pl. 19, figs 1–6, pl. 22, figs 1–3, 1998 ( Figs 45–50 )

Valves almost linear, with a gentle protuberance in the median region of the valve, absent in smaller valves. Valve apices apiculate, cuneate-apiculate and attenuate-rounded. Valve length 25.0–80.8 μm, valve width 8.5–12.2 μm (measured at the center). Areolae easy to discern in LM. Transapical striae almost equidistant spaced 7–10 striae in 10 μm, parallel in the middle of the valve, and curved-radiated at the apices, interrupted close to the ventral margin. Terminal nodules close to the poles, terminal raphe fissures long.

Material examined: — BRAZIL. Mato Grosso do Sul: Taguaruçú, Patos Lake , Upper Paraná River Floodplain , sediment, 23.III.2018, Ruwer et al. ( Nupélia UEM 18101–120) .

Figures

FIGURES 37–44. Eunotia monodon from Patos Lake and Garças Lake sediment samples, Upper Paraná River floodplain, Brazil. 37–43. LM. 44. SEM, external view of valve. Scale bars = 10 μm.

FIGURES 45–50. LM micrographs of Eunotia neomundana from Patos Lake sediment, Upper Paraná River floodplain, Brazil. Scale bar = 10 μm.