Biogeography and past history of ichthyological faunas

Ichthyological faunas established themselves and evolved as a consequence of the history of the aquatic systems they occupy. At various timescales, certain basins were colonized from other basins, and such colonizations were sometimes followed by selective extinctions resulting from geological and/or climatic events. The genesis and continued existence of aquatic habitats depend on two main factors: their morphology, which may change over the long term as a result of erosion or tectonics; and their hydrologic budget, which is dependent on precipitation, evaporation, infiltration, and for which slight changes may lead in the short or medium-term to either the drying out or expansion of the aquatic milieu in question, depending on the basin’s shape. Simultaneously, some species were able to give rise to others, and these speciation events often explain the presence of centres of endemism.Biogeography is the discipline that seeks to explain the distribution of organisms and the relationships between the areas of distribution of different species, by attempting to reconstruct the series of events that led to the present situation. To describe the relationships between the establishment of faunas and the spatio-temporal history of the physical systems, scientists need to draw up the most exhaustive inventories possible for different regions