* Fragilaria tenera var. nanana (Lange-Bertalot) Lange-Bertalot & S.Ulrich (2014: 7)

Figs 3: AL–AO

Length: 45.1–67.1 µm; width: 1.9–3.1 µm; striae: 20–22 in 10 µm (n = 30)

Taxonomical remarks: the individuals from Cascavel river micro-watershed contain a higher striae number (18.5–20 in 10 µm) than the original description. However, the authors pointed out that their specimens had lower striae density compared to the protologue provided by Meister (Lange-Bertalot & Ulrich 2014).

Teratological form: deformed valve outline, undulated.

Figs 3: AN–AO

Length: 45.1–54 µm; width: 2.1–2.5 µm; striae: 21–22 in 10 µm (n = 3)

Occurrence: S3.

Ecological characteristics: Cond.: 38.00–40.00 µS cm –1; BOD: 1.49–3.27 mg L− 1; COD: 7.23–8.08 mg L− 1; N-NH: 316–378 µg L− 1; 3 −1 −1 − −1 −1 NO: 0.37 mg L; DO: 11.42–14.57 mg L; pH: 5.79–6.19; PO: 0.006 –0.008 mg L; TP: 0.010 –0.017 mg L; TS: 38.00–66.00 3 4 mg L− 1; Temp.: 17.37–17.50 °C; Turb.: 7.03–10.70; Flow: 0.47 m 3 s; Average depth: 0.19–0.23 m; Prec.: 9.96 mm.

Metal concentrations: Co: 23.91–33.57 mg L –1; Cr: 27.33–78.86 mg L –1; Cu: 197.55–235.49 mg L –1; Mn: 398.50–444.52 mg L –1; Ni: 31.80–69.89; Pb: 35.58–46.56 mg L –1; Zn: 93.81–167.31 mg L –1.