Qualitative Planktonproben, die in den Jahren 1985 und 1986 in dem tropischen
Lago do Macaco, einem Ufersee des Rio Trombetas, einem der aus dem Nordwesten kommenden
Nebenflüsse des Amazonas, gezogen wurden, sind auf ihren Gehalt an Rotatorien untersucht
worden. Es wurden auffallend viele endemische Arten der Neotropis gefunden, insgesamt
12 von 49. Sechs seltene (Anuraeopsis sioli KOSTE; Ascomorpha klementi HAUER; Brachionus
gessneri HAUER; Brachionus urceolaris amazonica KOSTE& ROBERTSON; Keratella nhamunda
KOSTE& ROBERTSON; Paranuraeopsis quadriantennata KOSTE)und zwei Modifikationen (Trichocerca
pusilla LAUTERBORN 1898 nov. f. grandis und Trichocerca similis (WIERZEJSKI 1893) f. grandis
nach HAUER)werden mit Unterstützung von Abbildungen besprochen.

For the first time plankton sampies from Lake Macaco, which lies on the eastern shore
of the River Trombetas, Amazon, Brazil, were investigated for rotifers. This lake is situated in a
region in which the Rotifera Fauna has scarcely been studied. The microscopical research of the
material resulted in 48 cosmopolitical, tropical and subtropical species. The Bdelloidae were not
identifiable, because they were found most as preservation artifacts. Some specimen of this
taxon may belong to the genera Philodina and Rotaria. 14 species were endemics of Neotropis.
New information about taxonorny, ecology and distribution of some interesting and rare animals
was able to be added. These are: Anuraeopsis sioli KOSTE, Ascomorpha klementi (HAUER),
Brachionus urceolaris amazonica KOSTE & ROBERTSON,Keratella nhamunda (KOSTE& ROBERTSAN),
Paranuraeopsis quadriantennata KOSTE,Trichocerca pusilla (LAUTERBORN,1898) f. grandis
nov. forma and Trichocerca similis (WIERZEJSKI,1893) f. grandis after HAUER 1965.