Nine taxa of colorless Euglenophyta are presented as a result of a taxonomic study in lentic environments (lagoons, wetlands, pond, and canal) of two areas near Patos Lagoon: Casamento Lake and associated ecosystems (30º03'-30º34'S; 50º25'-50º47'W) and the Butiazal de Tapes region (30º23'- 30º38'S; 51º16'- 51º29'W) on the Coastal Plains of Rio Grande do Sul. Sampling with nets and pressed macrophytes were carried out during fall and spring 2003. All nine taxa are new reports for the Coastal Plains of the state, where Cyclidiopsis acus Korsch. Entosiphon polyaulax Skuja, Gyropaigne kosmos Skuja, Menoidium tortuosum (Stokes) Lemm. var. playfairii Bour. and Rhabdomonas mirabilis (Playf.) Schroeckh, Lee & Patterson are first reports for Brazil, and Menoidium gracile Playf., Menoidium pellucidum Perty and Menoidium obtusum Pringheim for Rio Grande do Sul. The wetland ecosystem had the highest richness, where seven of the nine identified taxa were found in the wetlands between Capivari and Casamento lakes. The Casamento Lake area had higher richness of colorless Euglenophyta than the habitats in the Butiazal de Tapes region, probably because Casamento Lake received a higher anthropic contribution.
Colorless Euglenophyta; taxonomy; southern Brazil
