Biodiversidade e distribui？？o das diatomáceas (Bacillariophyceae) de sedimentos superficiais nos reservatórios em cascata do rio Paranapanema, SP/PR, Brasil

paper presents the taxonomic survey and distribution of diatoms (class bacillariophyceae) from the surface sediments of five cascading reservoirs of the paranapanema river. samples were dredged from three sampling stations (upstream, middle portion, and close to the dam) of reservoirs. 44 taxa belonging to 22 genera were identified, 23 (52.3%) of which represent new records for the paranapanema river basin, four (9.1%) for the s？o paulo state, and two (4.5%) for the paraná state. morphometric data, relevant comments, and local spatial distribution of species in the s？o paulo and paraná states are available. taxonomic richness was markedly greater in the first reservoir (jurumirim) and in the sampling station with influence of the tibagi river. present work is a pioneer contribution to the country in regard to biodiversity and spatial distribution of diatoms in cascade reservoirs, contributing for future studies on conservation and monitoring of the paranapanema river basin.