The nature of adaptive radiation in the cichlid fishes of Lake Tanganyika

Adaptive radiation is probably the source of much of the ecological and morphological diversity of life on Earth.

Because of their spectacular taxonomic, phenotypic, ecological and behavioral diversity and their propensity for explosive speciation, the cichlid populations in the African Great Lakes of Victoria, Malawi and Tanganyika are an excellent example of this evolutionary process. The cichlids of Lake Tanganyika form the most morphologically, ecologically and behaviorally diverse cichlid species groups.

Our in-depth study of almost all of its approximately 250 cichlid species revealed that this spectacular adaptive radiation did not occur gradually, but in the form of three successive and trait-specific pulses of accelerated phenotypic evolution.

Three trait complexes - body shape, mouth morphology and lower jaw bone - are very diverse and show a particularly strong relationship with the environment. Furthermore, there is evidence that diversification in terms of behavior and pigmentation patterns has contributed to the adaptive radiation of cichlids in Lake Tanganyika.