Pliocene isolation of a north-west Saharan cichlid fish.

The evolutionary origin of the only north-west Saharan haplochromine cichlid, Astatotilapia desfontainii, was explored using mitochondrial DNA sequences. Phylogenetic analyses revealed that this species belonged to the main East African-Nilotic haplochromine clade, but was a distinct lineage that diverged from modern haplochromines in the Pliocene. The results suggest that A. desfontainii is a relict haplochromine lineage that has endured major climate fluctuations in North Africa.