SISTEMATIC AND BIOGEOGRAPHY OF FISHES FROM SMALL STREAMS

Abstract

The freshwater fish fauna occurring in Brazilian small streams comprises 34 families of teleosts. The knowledge about its sistematic and biogeography is characterized by great heterogeneity among taxonomic groups. For some groups there are identification keys and phylogenetic hypotheses available which can be used for detailed biogeographic studies. Over the last few years, the biogeographic studies of small stream fish faunas reflect a general trend of rejection of dispersalist ideas as the primary explanation for the spatial diversity of the neotropical fish fauna and of simple inventaries of arcas of endemism. Recent biogeographic studies rely on the formulation of hypotheses about the biogeographic history of river drainages based on the identification of geographic barriers associated with geologic, climatic and eustatic events of the past. Such events are the primary cause of vicariant differentiation of the fish fauna.