Freshwater Fishes and Biogeography of Central America and the Antilles

Abstract

Within ancient lineages of teleostean fishes are certain families that are almost completely intolerant of saltwater and have apparently been so throughout their history. These families are called freshwater fishes (Myers, 1938), and most biogeographers consider that their present distribution in the world must have been achieved by means of freshwater pathways. In almost all parts of the world to which they have been able to gain access, the primary ostariophysan fishes (a monophyletic group with a Weberian apparatus for sound transmission between the swim bladder and the inner ear) have become the dominant groups. They comprise a complex of 57 families with more than 5,000 species accounting for about 73% of the world's freshwater species (Nelson, 1976). In contrast, secondary freshwater fish families typically have a high salinity tolerance and their distribution patterns often indicate the ability to cross saltwater barriers (Myers, 1938).