Testate amoeba distribution in a paludal environment from Capão do Leão, Mostardas, Rio Grande do Sul State, Brazil

Abstract

The results of the content in testate amoeba from sedimentary samples collected in winter and summer seasons at Capão do Leão region, Coastal Plain of Rio Grande do Sul State, southernmost Brazil, are presented. The analysis confirm the paludal character and acid pH nature of the water body by the significant occurrence of Bullinularia indica and by the richness of Difflugiidae, with dominance of Centropyxidae, represented by Centropyxis platystoma. Centropyxis discoides and Nebela dentistoma are exclusive of the winter assemblage in the area, whereas Difflugia avellana only occurs in the summer samples. In spite of the distinct number of specimens found between the summer and winter collects, the similarity analysis and t-test applied do not show significant results. Centropyxis aeröphila var. sylvatica, Nebela dentistoma, Difflugia gramen, and Difflugia oblonga var. venusta are recorded in coastal plain deposits of the Rio Grande do Sul for the first time.

Key words: testate amoebae, paludal environment, coastal plain, Rio Grande do Sul, Brazil.