The Cichlid Fishes of Lake Malawi, Africa

Abstract of Publication

Moran, P., I. Kornfield, and P. Reinthal. 1994. Molecular systematics and radiation of the haplochromine cichlids (Teleostei: Perciformes) of Lake Malawi. Copeia 1994: 274-288.  

Mitochondrial DNA (mtDNA) restriction fragment length polymorphisms were assayed among 40 species of Lake Malawi haplochromines (Cichlidae) including representatives of ecologically divergent genera. Six distinctive mtDNA lineages were distinguished, two of which were major clades, represented by a large number of species. The other four lineages were each represented by a single species with a divergent mtDNA haplotype. One of the two major clades was composed of the shallow-water, rock-dwelling mbuna species, whereas the other included a diverse array of sand-dwelling and pelagic species. A number of taxa, found to be firmly embedded within the mbuna clade, are quite distinct in morphology and generally inhabit deeper, sediment-rich areas rather than the rocky habitats typical of other mbuna. The mbuna group is generally thought to be a monophyletic assemblage, but these results suggest that it is actually paraphyletic. In contrast to the high morphological diversity among Malawi haplochromine species, mtDNA sequence divergence was found to be remarkably low. This finding underscores the unprecedented rapidity of speciation and evolutionary plasticity in this fish species flock.




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