So many fishes, so little time: An overview of recent ichthyological discovery in continental waters

Although freshwaters contribute only about 0.01% to Earth's water supply, t heir fishes now number more than 10,000 species and thus account for at lea st 40% of all fish species. The continental fish fauna differ greatly in ta xonomic composition and species richness, our state of knowledge of them, a nd the rate of discovery of unknown kinds. The ichthyofaunas of North Ameri ca (about 1050 species), Europe (about 360), and Australia-New Guinea (abou t 500), are the most thoroughly documented, but new species continue to be described based on discovery of previously unseen forms and species-level t axonomic splits of known species. The ichthyofaunas of tropical Asia (perha ps > 3000), Africa (perhaps > 3000 species), and South and Central America (perhaps >> 5000 species), are species-rich yet incompletely known. Tropica l freshwaters are the hot spots of recent and likely future ichthyological discoveries. Especially in the tropics, discoveries of species that signal new generic-level taxa are common, and new family-level groups are found oc casionally. Everywhere ongoing phylogenetic studies often suggest or reveal unsuspected relationships. These are times of exciting discovery and advan cement of knowledge in freshwater ichthyology. New discoveries beckon us to seek the many remaining unknowns in the diversity of life on our planet. T hese are also times of rapid and destructive change in freshwater habitats around the globe. These threats alert us to the increasing potential for pe rmanent loss and ignorance of much of our planet's rich aquatic biota.