Ref ID : 2834
Gerd-Oltmann Brandorff, Walter Koste, and Nikolai N. Smirnov; The Composition and Structure of Rotiferan and Crustacean Communities of the Lower Rio Nhamunda, Amazonas, Brazil. Studies on Neotropical Fauna and Environment 17:69-121, 1982
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The crustaceans and rotifers of 17 samples from the plankton and 3 from the littoral from lakes of the lower Rio Nhamunda, an affluent of the Amazon were studied. 145 taxa of rotifers and 46 of crustaceans were found; two rotifers and three crustaceans are new to science; Keratella americana nhamundaiensis, Euchlanis triquetra var. nhamudaiensis, Echinisca superaculeata, E. sioli, and E. mira. In the taxonomical part 24 rotiferan and 22 crustacean taxa are described in more detail, drawings of them given, and partly remarks made about the geographical distribution. In the biocenotical part the conditions of dominances were studied: Brachionus zahniseri and Keratella americana within the rotifers and Bosminopsis deitersi and Oithona amazonica within the crustaceans are the dominant species in the pelagial. In the littorial Synchaeta stylata and Streblocerus pygmaeus were found to be dominant. The species diversity and also the evenness is higher within the rotifers than in the crustaceans. By means of an index of similarity dendrograms were drawn where groups of lakes can be differentiated by using the similarity between the crustaceans. The proportion of neotropical species in relation to pantropical and cosmopolitical species is lowest in the rotifers, higher in the cladocerans and highest in the copepods at 100%.