The genera Staurastrum Meyen ex Ralfs and Staurodesmus Teiling of the periphytic community of the Rosana Reservoir, Paraná/São Paulo, Brazil

Abstract

The desmids are microscopic green algae that occur in all aquatic environments and is currently represented by a large number of species distributed in 60 genera. In this study we identify and describe species of the genera Staurastrum and Staurodesmus (Desmidiaceae, Zygnemaphyceae) in periphytic algal community of the Rosana Reservoir (Paraná/São Paulo). Samples were collected in three regions of the reservoir: riverine, transitional, and lacustrine, along the axis of the river-dam, in April and August 2002, in patterned substrate (petioles of Eichhornia azurea (Sw.) Kunth). Among the 37 species identified, 26 were distributed in the genus Staurastrum e 11 in the Staurodesmus, with 34 occurrent in April and 22 August. Between regions higher species richness occurred in the lacustrine region of both sampling periods (28 and 20, respectively). Staurastrum dilatatum (Ehrenberg) Ralfs was classified as common, occurring in 100% of the samples. The species S. ambiguum Turner and S. claviferum West & West occurred in 83.3% of the samples.