No abstract

A new device to sample freshwater benthic macroinvertebrates was used in a low and sandy stretch of a Brazilian sub-tropical river (the River Cai, Triunfo, RS) and in one of its small tributaries, Bom Jardim brook (Arroio Bom Jardim). In this study, the effectiveness of this device, a PET sampler, was tested at different sites in the river and the brook throughout the four seasons between 2001-2002. Comparisons were made by PCA and ANOVA, both employing a bootstrap procedure based on similarity matrices. The PET sampler proved to be a reliable tool for detection of seasonal and spatial differences in richness, total abundance of organisms, and Shannon's diversity index in both river and brook and is therefore recommended for use in the monitoring of macroinvertebrate communities in this system.

Corvomeyenia epilithosa sp. nov. é descrita e registrada para área preservada no Sul do Brasil. São atualizadas a definição e a distribuição do gênero Corvomeyenia Weltner, 1913 propostas por Manconi & Pronzato (2002). É apresentada chave taxonômica para as quatro espécies do gênero: C. everetti (Mills, 1884) e C. carolinensis Harrison (1971), para a Região Neártica, C. thumi (Traxler, l895) e C. epilithosa sp. nov. para a Região Neotropical. São comentadas distinções significativas de habitat dessas espécies.