Taxonomic studies of the Rotifera (Phylum Aschelminthes) from a Central Amazonian varzea lake, Lago Camaleão (Ilha de Marchantaria, Rio Solimões, Amazonas, Brazil)

148 species of rotifers were identified in 22 plankton samples collected in Lago Camaleão, situated on the Ilha de Marchantaria, in the varzea region of the Solimões-Amazonas River system. During the low water period, February, 1981, 33 species were found. During the high water period, July, 1981, after the development of the aquatic vegetation, 138 species were identified. The decomposition of the inundated terrestrial vegetation favors those rotifer species which live on the surface of putrid mud. All are cosmopolitan species of the genera Lepadella, Mytilina, Platyias, Brachionus and Testudinella. Bdelloidea was represented by several species of the genus Rotaria. Several identification errors of former authors were revised, and in this study the following are proposed: Brachionus urceolaris amazonica n. ssp., Keratella nhamunda nov. nom., Lecane (s. str.) aimazoniana nov. nom., Lecane aspasia amazonica n. ssp. New records for the Amazon region include: Lecane (s. str.) stichaeoides HAUER 1938, Mytilina unguipes (LUCKS 1912), Testudinella greeni KOSTE 1981, and Testudinella patina dendradena (DE BEAUCHAMP 1955). Three new taxa are described: Cephatodelta paggia n. sp., Lecane (Monostyla) marchantaria n. sp., and Lepadella (L.) minoruoides n. sp