Evolution of South American stream fish fauna: broad patterns and possible causal processes

Abstract

A short description of the South American freshwater fish fauna taxonomic/phyletic composition and general level of biological knowledge is furnishecl, followecl by a search - based on data frorn the literature and from four chosen southeastern brazilian strearns - for streams ichthyofauna's common broadevolutionary patterns and processes, At the paper's end evolutionary patterns associated with small aclult size, the only common general pattern found associated to the fish species of ali four ichthyofaunas, are listed. Finally, the possible importance of vicariance, alopatric speciation ancl heterochrony in South American stream Iishes evolution is pointecl out.