A morphological and molecular analysis of the species diversity of the cichlid genus Petrochromis from Lake Tanganyika (Teleostei: Cichlidae)

Abstract

A taxonomic revision of the cichlid fish genus Petrochromis endemic to Lake Tanganyika. All recognized taxa are herein described, one subspecies is given species status and five new species, viz. P. calliris, P. daidali, P. heffalumpus, P. lisachisme and P. paucispinis, are presented. P. calliris is described from 6 specimens from Cape Mpimbwe, and distinguished primarily by having a high number of both gill rakers on the lower limb of the first gill arch and vertebrae. P. daidali is described from 18 specimens from Cape Mpimbwe, Kansombo and Nkwazi point, and distinguished primarily by males having a labyrinth-like pattern on the head. P. heffalumpus is described from 7 specimens from Cape Mpimbwe, and distinguished primarily by its great size. P. lisachisme is described from 12 specimens from Cape Mpimbwe and Lyamembe, and distinguished primarily by having a high number of dorsal spines. P. paucispinis is described from 4 specimens from Halembe, and distinguished primarily by having a low number of dorsal spines. A revised key to Petrochromis is included. A phylogenetic tree hypothesis of the genus, based on molecular (mitochondrial cytochrome b and d-loop) and morphological results show that jaw position and number of vertebrae are important diagnostic characters. Analyses suggest that the \"ancestral Petrochromis\" might have looked something like P. orthognathus.