Comparative morphology, phylogeny, and classification of West African callopanchacine killifishes (Teleostei: Cyprinodontiformes: Nothobranchiidae)

Abstract

A phylogenetic analysis combining 63 morphological characters and DNA sequences (3296 bp), comprising segments of the mitochondrial genes 16S and ND2, and the nuclear gene 28S, for 19 taxa of the West African killifish tribe Callopanchacini and 11 out-group taxa, highly supported the monophyly of the tribe, and made it possible to provide the first unambiguous diagnoses for the included genera (Archiaphyosemion, Callopanchax, Nimbapanchax, and Scriptaphyosemion). The monophyly of the Callopanchacini is supported by six morphological synapomorphies: posterior portion of the mandibular channel consisting of a single open groove; basihyal pentagonal, as a result of a nearly rectangular basihyal cartilage and a triangular bony support; dorsal process of the urohyal usually absent, sometimes rudimentary; presence of a wide bony flap adjacent to the proximal portion of the fourth ceratobranchial; a broad bony flap adjacent to the proximal portion of the fifth ceratobranchial; and haemal prezygapophysis of the pre-ural vertebra 2 ventrally directed. The analysis indicates that the medially continuous rostral neuromast channel, commonly used to diagnose the tribe, is plesiomorphic. This study also indicates that, among African aplocheiloids, the annual life cycle style developed once in Callopanchax, and then again independently in the clade containing Fundulopanchax and Nothobranchius. © 2015 The Linnean Society of London