Fish, upper Purus River, state of Acre, Brazil.

The ichthyofauna of the headwaters of the main tributaries of the mighty Solimões/Amazonas River hasbeen little studied. Considering the importance of those environments for the overall fish diversity in that river system,we surveyed the composition of the fish fauna of the upper portion of Purus River and two of its tributaries (Caeté andMacapá rivers), state of Acre, Brazil. The collections were done in November 2004, using a seine net and a set ofgillnets of different mesh sizes. A total of 735 specimens belonging to 86 species and 28 families were collected. Eightspecies, Creagrutus occidaneus, Phenacogaster pectinatus, Prionobrama filigera, Moenkhausia cf. lepidura,Leptagoniates pi (Characidade), Henonemus punctatus (Trichomycteridae), Toracocharax stellatus (Gateropelecidae),and Eigenmannia macrops (Sternopygidae) composed nearly half of the specimens collected. This survey adds 48 newrecords to the ichthyofauna of Purus River and elevates to 243 the number of known fish species in that river, but agreater sampling effort is necessary to produce a reasonably complete picture of the fish diversity in the basin