title: Ancient divergence in bathypelagic lake tanganyika deepwater cichlids: mitochondrial phylogeny of the tribe bathybatini.
abstract: The cichlid species flock of Lake Tanganyika represents a polyphyletic assemblage of eight ancestral lineages, which colonized the emerging lake independently. Our study is focused on one of these lineages, the Bathybatini, a tribe of specialized piscivorous cichlids of the deep pelagic zone. By analyzing three mtDNA gene segments of all eight species of the tribe and two species of the closely related Trematocarini, we propose on the basis of a linearized tree analysis that the Bathybatini comprise two distinct lineages, the genera Hemibates and Bathybates, that seeded the primary lacustrine Tanganyika radiation independently. The genus Hemibates is likely to represent a distinct lineage that emerged simultaneously with the tribe Trematocarini and the genus Bathybates and should be therefore treated as a distinct tribe. Within the genus Bathybates, B. minor clearly represents the most ancestral split and is likely to have diverged from the remaining species in the course of the "primary lacustrine Tanganyika radiation" during which also the radiations of the Lamprologini and the H-lineage took place. The remaining "large" Bathybates species also diversified almost simultaneously and in step with the diversification of other Tanganyikan lineages-the Limnochromini and Cyprichromini-with B. graueri occupying the most ancestral branch, suggesting that these were induced by the same environmental changes. The lack of geographic color morphs suggests that competition and resource partitioning, rather than allopatric speciation, promoted speciation within the genus Bathybates.
authors.affiliation: Department of Zoology, Karl-Franzens-University of Graz, Austria.
authors.forename: Stephan
authors.initials: S
authors.lastname: Koblmüller
authors.forename: Nina
authors.initials: N
authors.lastname: Duftner
authors.forename: Cyprian
authors.initials: C
authors.lastname: Katongo
authors.forename: Harris
authors.initials: H
authors.lastname: Phiri
authors.forename: Christian
authors.initials: C
authors.lastname: Sturmbauer
mesh_terms: D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D023681:Cichlids / Q000145:classification* / Q000235:genetics*; D016000:Cluster Analysis; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000235:genetics; D015023:Democratic Republic of the Congo; D004777:Environment; D019143:Evolution, Molecular; D005618:Fresh Water; D005843:Geography; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013636:Tanzania
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial