Cichlid Fish Diversity and Speciation
Cichlids are one of the most species rich families of vertebrates, with conservative estimates citing more than 2,000 extant species. Although native to tropical areas of the world, with the exception of Australia, some 70-80% of cichlids are found in Africa, with the greatest diversity found in the Great Lakes (lakes Victoria, Tanzania and Malawi). Their highly integrated pharyngeal jaw apparatus permits cichlids to transport and process food, thus enabling the oral jaws to develop specialisations for acquiring a variety of food items. This distinct feature has allowed cichlids to achieve great trophic diversity, which in turn has lead to great species diversity. The high species diversity of this vertebrate family is not accompanied by an appropriately high genetic diversity. The combination
of rapid radiation of the group and relatively low genetic diversity has confounded attempts to diagnose species and discern phylogenetic relationships. Behavioural traits appear to be important characters for diagnosing many cichlid species.