Molecular phylogeny and taxonomic revision of the cichlid genus Hemichromis (Teleostei, Cichliformes, Cichlidae), with description of a new genus and revalidation of H. angolensis

The tribe Hemichromini is an early diverging, mainly Central and West African lineage within the species-rich African cichlid fishes (Cichliformes, Cichlidae) including two genera, Hemichromis Peters 1858 and the monotypic Anomalochromis Greenwood 1985. Though many of the species are popular aquarium fish, the number of hemichromine species is still a matter of debate with their phylogenetic relationships largely unknown. Based on DNA sequence data of two mitochondrial and two nuclear genes, we present the first comprehensive phylogeny of the Hemichromini. Using an integrative approach based on these DNA sequences data, morphometrics, meristics, and a qualitative assessment of body coloration, we revise the genus Hemichromis and discuss intrageneric relationships. Two major groups within the genus Hemichromis that diverged roughly 6–12 MYA are recognized, of which the first one represents Hemichromis sensu stricto, for the second one a new genus, Rubricatochromis, is described. Diversification with these two main groups started about 3–6 MYA, with different trajectories of colonization in the two groups. Hemichromis populations from the most southern (Cuanza, Zambezi, and Okavango) part of the genus’ distribution range constitute a well-supported clade distinct from all other members of Hemichromis, for which the taxon H. angolensis Steindachner, 1865 is confirmed.