New records of diatoms (Bacillariophyta) for the State of Rio Grande do Sul and Brazil

ABSTRACT

The study of the biodiversity of diatoms in lotic environments in the Environmental Protection Area of the Ibirapuitã, in the southwest of Rio Grande do Sul, revealed the presence of 21 species of pennate diatoms, belonging to several families, which are new records for the state and/or country. Among the registered taxa, 57% have a wide distribution in the continents, and 43% are restricted to South America. The species that were abundant were Cocconeis amerieuglypta, Cymbella tropica, C. turgidula, Denticula kuetzingii, Encyonopsis subminuta e Gomphonema graciloides. We present descriptions of the taxa's morphological and metric characteristics, illustrations, and geographic distribution.

Keywords:
biodiversity; lotic environments; microalgae; taxonomy