** Pinnularia laucensis Lange-Bertalot (2000: 200)

Figs 9: J–K

Length: 15.5–26.3 µm; width: 3.6–4.5 µm; striae: 12–15 in 10 µm (n = 23)

Taxonomical remarks: This taxon was originally described from high-altitude (4000 m) and acidic (pH = 5) river samples from Chile (Rumrich et al. 2000). The individuals found in Cascavel river micro-watershed are similar to Pinnularia laucensis, except for being slightly larger than the original description (length: 13–20 µm; width: 3.3–4 µm), but similar striae density (11–14 in 10 µm). Pinnularia sinistra Krammer (1992: 105), the most similar taxon, can be differentiated by the subrostrate apices and more radiate striae (Krammer 1992).

Teratological form: not observed.