We critically compared local populations of the bulldog fish, Marcusenius macrolepidotus (Peters 1852Peters, W. C. H. 1852. Einige neue Säugethiere und Flussfische aus Mossambique.. Monatsberichte der Königlich‐Preussischen Akademie der Wissenschaften Berlin, 1852: 273–276. [Google Scholar]), from different watersheds, from the furthest south (28° South, South Africa) to the Equator in Kenya. We ascertained allopatric differentiation from topotypical M. macrolepidotus from the Lower Zambezi River (Mozambique) in morphology, electric organ discharges, and molecular genetics for: (1) samples from the Okavango and Upper Zambezi Systems (Botswana and Namibia), (2) samples from South Africa's rivers draining into the Indian Ocean, and (3) samples from the East African Tana River (Kenya). Significant genetic distances in the mitochondrial cytochrome b gene and differing ISSR‐PCR profiles corroborate differentiation between the four taxa. We resurrect M. pongolensis (Fowler, 1934Fowler, H. W. 1934. Fishes obtained by Mr. H. W. Bell‐Marley chiefly in Natal and Zululand in 1929 to 1932.. Proceedings of the Academy of Natural Sciences of Philadelphia, 86: 405–514. [Google Scholar]) for South Africa (sample 2), and M. angolensis (Boulenger, 1905Boulenger, G. A. 1905. Descriptions of four new freshwater fishes discovered by Dr. W. J. Ansorge in Angola.. Annals and Magazine of Natural History (Ser. 7), 15(89): 457–459.[Taylor & Francis Online], , [Google Scholar]) for the Quanza River/Angola. We recognize M. altisambesi sp. n. for the Upper Zambezi/Okavango specimens (sample 1), and M. devosi sp. n. for those from Kenya (sample 3). Keywords: Teleostei, Mormyridae, Marcusenius, systematics, morphometrics, electric organ discharges, molecular genetics, southern Africa.