Periphytic diatoms on Potamogeton polygonus Cham. & Schltdl.: first records from Parana State

Periphytic diatoms on Potamogeton polygonus Cham. & Schltdl.: first records from Parana State. A taxonomic study of periphytic diatoms associated to aquatic macrophyte Potanzogeton polygonus was carried out. Specimens were collected on February, May and November/2005 and March/2006, in an artificial lagoon and in the Salto Amazonas river, located at General Cameiro, Parana State. Based on the analysis of permanent slides with cleaned periphytic samples, one hundred and forty-seven taxa had been registered, 55 diatoms were exclusive of the lentic environment, 34 of the lotic environment and 58 occurred on both ones. The most representative families were Eunotiaceae (13.6%), Pinnulariaceae (11.6%) and Naviculaceae (9.6%). The genera with greater number of species and varieties were Eunotia with 20 taxa and Pinnularia with 17. The study contributed with 18 new registers to the state, and was pioneer to document forms of diatom attachment on aquatic macrophyte of systems lotic and lentic in the Parana state.