title: Repeated trans-watershed hybridization among haplochromine cichlids (Cichlidae) was triggered by Neogene landscape evolution.
abstract: The megadiverse haplochromine cichlid radiations of the East African lakes, famous examples of explosive speciation and adaptive radiation, are according to recent studies, introgressed by different riverine lineages. This study is based on the first comprehensive mitochondrial and nuclear DNA dataset from extensive sampling of riverine haplochromine cichlids. It includes species from the lower River Congo and Angolan (River Kwanza) drainages. Reconstruction of phylogenetic hypotheses revealed the paradox of clearly discordant phylogenetic signals. Closely related mtDNA haplotypes are distributed thousands of kilometres apart and across major African watersheds, whereas some neighbouring species carry drastically divergent mtDNA haplotypes. At shallow and deep phylogenetic layers, strong signals of hybridization are attributed to the complex Late Miocene/Early Pliocene palaeohistory of African rivers. Hybridization of multiple lineages across changing watersheds shaped each of the major haplochromine radiations in lakes Tanganyika, Victoria, Malawi and the Kalahari Palaeolakes, as well as a miniature species flock in the Congo basin (River Fwa). On the basis of our results, introgression occurred not only on a spatially restricted scale, but massively over almost the whole range of the haplochromine distribution. This provides an alternative view on the origin and exceptional high diversity of this enigmatic vertebrate group.
authors.affiliation: Bavarian State Collection of Zoology, Münchhausenstrasse 21, Munich, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Schwarzer
authors.forename: Ernst Roelof
authors.initials: ER
authors.lastname: Swartz
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Vreven
authors.forename: Jos
authors.initials: J
authors.lastname: Snoeks
authors.forename: Fenton Peter David
authors.initials: FP
authors.lastname: Cotterill
authors.forename: Bernhard
authors.initials: B
authors.lastname: Misof
authors.forename: Ulrich Kurt
authors.initials: UK
authors.lastname: Schliewen
mesh_terms: D000349:Africa; D054458:Amplified Fragment Length Polymorphism Analysis; D063147:Animal Distribution; D000818:Animals; D005075:Biological Evolution; D023681:Cichlids / Q000145:classification / Q000235:genetics*; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D019419:Evolution, Planetary; D006824:Hybridization, Genetic; D060106:Lakes; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000235:genetics; D010802:Phylogeny; D045483:Rivers; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b; D009245:NADH Dehydrogenase