Complete mitochondrial genomes of riverine Lamprologus (Actinopterygii, Cichlidae) with an emphasis on the blind cichlid L. lethops

Lamprologine cichlids are a diverse group of fishes distributed in Lake Tanganyika and the Congo River. Nine species of Lamprologus occur in the Congo River basin including the only blind cichlid Lamprologus lethops, but little is known about the natural history and evolution of this enigmatic species. To alleviate this knowledge gap, we characterized the complete mitochondrial genomes of L. lethops and its riverine congeners and provided a phylogenetic hypothesis based on these data. We recovered complete mitochondrial genomes from eleven specimens of eight species of Lamprologus. Mitogenomes were identical in the number and order of genes and similar in size (16,579-16,587 bp). In contrast to previous phylogenomic studies, riverine Lamprologus were recovered in two non-sister mitochondrial lineages that were more closely related to other genera of Lake Tanganyika lamprologines than to each other. In the first lineage, most relationships were not highly supported. In the second lineage, L. lethops was recovered as the sister species of L. markerti, L. mocquardi and L. tigripictilis. Interestingly, sequences from L. mocquardi were found in the two mitochondrial lineages. Our results hint at multiple events of past introgression and highlight the importance of increasing taxonomic and genomic sampling to study complex evolutionary histories.