Phylogeny and age of chromidotilapiine cichlids
Chromidotilapiine cichlid fishes (Teleostei: Cichlidae) of West and Central Africa represent the most species rich ancient African cichlid lineage. In contrast to the mega-diverse haplotilapiine cichlids from the African rift valley and crater lakes, very little is known about their phylogenetic history. Based on mitochondrial and nuclear DNA sequences and a representative taxon sampling, we present a first molecular phylogenetic hypothesis and propose age estimates for their origin and diversification. Our data support the monophyly and an Oligocene/Eocene origin of chromidotilapiines. Within chromidotilapiines, two large, reciprocally monophyletic clades are present and the enigmatic genus Teleogramma could be phylogenetically placed for the first time. The two distantly distributed species Limbochromisrobertsi and Chromidotilapiaschoutedeni were identified as sister group to the Congolian species complexes of Nanochromis and Congochromis. This unexpected phylogenetic link between a region in West Africa and the Congo basin suggests an ancient hydrogeographic corridor spanning almost half of the African continent. The nearly complete taxon sampling, good knowledge on species distribution patterns and well resolved phylogenies allow the presumption that paleogeographic patterns rather than ecological factors shaped the ancient divergence within chromidotilapiines, which predates the origin of the mega-diverse austrotilapiine lineage, comprising the majority of African cichlid species.