Allopatric differentiation in the Marcusenius macrolepidotus species complex in southern and eastern Africa: the resurrection of M. pongolensis and M. angolensis, and the description of two new species (Mormyridae, Teleostei)

Abstract

We critically compared local populations of the bulldog fish, Marcusenius macrolepidotus (Peters 1852), 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, 1934) for South Africa (sample 2), and M. angolensis (Boulenger, 1905) 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

Acknowledgements

For acting as generous hosts and making available base camps, as well as their efficient help during the collection of fish, we wish to thank Dez Weeks (then Zoology Department, Rhodes University, South Africa), as well as A.R. Deacon (who also gave permission) and P.J. Kotze (both from the Research Department, Kruger National Park). Johan Engelbrecht (Mpumalanga Parks Board) gave permission for, and assisted in, the sampling of fish from the Crocodile and Blyde Rivers. Wynand Vlok (University of the North, now Limpopo) gave logistical support and also assisted in catching fish. Johan Engelbrecht is thanked for organizing a successful sampling expedition to KwaZulu‐Natal (Mhlatuze and Pongola Rivers), and his assistance in the Okavango and Caprivi. For confirming electrophoretic results, we thank H.M. Beker (Animal Improvement Institute, Irene, South Africa). For two specimens from Nswananzi River, Ofer Gon (SAIAB). For taking anatomical measurements, we thank S. Singer and I. Kaunzinger who also recorded the reproductive activity of a male M. pongolensis in aquarium; for gonad histology, B. Otto. For additional measurements, Kathrin Kahler, Ellen Fröhlich, Peter Machnik, Henriette Seichert, Sabine Hartl, Birgit Blaul, Lena Dietz. For helping with EOD recordings on imported M. pongolensis of the third sample, we thank S. Hanika, S. Paintner and A. Scheffel, and for fish photographs, Stefan Buchhauser, Michael Lamml, Ellen Fröhlich and Peter Machnik. We thank Hedi Sauer‐Gürth (Heidelberg University) for carrying out the sequence determinations. We thank Roger Bills of SAIAB for sampling and making available Lower Zambezi bulldogs (both alive and preserved), and advice on systematic procedure; Dr. P. Bartsch, ZMB Berlin, for permission and support with studying the type material; Dr. L. Seegers, for photographs; Dr. A. Gill and Mr. James MacLaine, BMNH; the late Dr. G. Teugels, MRAC; Dr. J. Lundberg, ANSP; the late Dr. L. De Vos, Nairobi Museum, Kenya, organized an expedition to Tana River and provided also other support; Dr. K. Heine, E. Ardelean and E. Fröhlich for support with Figures 4 and 8; Dr. F. Fajen, Classical Studies, for advice with Latin species names, B. Markowski for proof‐reading an earlier version of the manuscript. Roger Bills, Ernst Swartz and Luis da Costa for critically reviewing the manuscript. Supported by travel grants and funding by Deutsche Forschungsgemeinschaft (grants SFB4/H1, and Kr 446/10‐1 through Kr 446/11‐3 to B.K.).