Quantitative and qualitative analyses developed with dead and living testate amoebae were carried out in Lagoa do Peixe National Park, near the central portion of the external coastal plain of the Rio Grande do Sul State, south of Brazil. Samples collected in bottom sediments from distinct lothic and lenthic environments show Difflugia oblonga, Pontigulasia compressa and Cucurbitella mespiliformis as the dominant species in the dead assemblages of the lenthic environments, the last two also present in the living assemblage. In the lothic dead assemblages the dominant species are Hoogenraadia africana, Centropyxis platystoma, D. oblonga and C. mespiliformis, the first three also dominating the living assemblage. Six species were exclusive from calm body waters and 10 to river streams, attesting more favorable conditions of life and/or preservation of these microorganims. A rare form of the freshwater foraminifer Plagiophrys sp. was observed for the first time. Key words: testate amoebae, Recent, Lagoa do Peixe National Park, Brazil.Análises quantitativas e qualitativas de amebas testáceas vivas e mortas foram realizadas nos ambientes límnicos situados no Parque Nacional da Lagoa do Peixe, porção central da planície costeira externa do Rio Grande do Sul. Os resultados mostram que entre as 36 formas identificadas, as espécies Difflugia oblonga, Pontigulasia compressa e Cucurbitella mespiliformis dominam as assembléias mortas dos ambientes lênticos, com as duas últimas igualmente importantes entre as formas vivas. Nos ambientes lóticos as espécies Hoogenraadia africana, Centropyxis platystoma, Difflugia oblonga e Cucurbitella mespiliformis, foram as mais freqüentes, com a ultima estando ausente das assembléias mortas. Seis espécies mostraram ser exclusivas dos ambientes lênticos e dez dos lóticos. Plagiophrys sp., forma rara de foraminífero de água doce, é registrado pela primeira vez. Palavras-chave: amebas testáceas, Parque Nacional da Lagoa do Peixe, Brasil
