Abstract
Here we examine new collections of Petrocephalus species (Osteoglossomorpha: Mormyridae: Petrocephalinae) made within Odzala National Park in the Republic of the Congo (Lékoli River drainage, northwestern Congo River basin). We compare these collections to type material of all nominal Petrocephalus species described from the Congo basin and the adjacent Lower Guinea ichthyofaunal province. Based on morphology and electric signal characteristics we recognize eleven distinct species of Petrocephalus in these collections, including five new species described herein: Petrocephalus binotatus, Petrocephalus zakoni n. sp., Petrocephalus valentini n. sp., Petrocephalus balayi, Petrocephalus microphthalmus, Petrocephalus odzalaensis n. sp., Petrocephalus christyi, Petrocephalus sauvagii, Petrocephalus pulsivertens n. sp., Petrocephalus grandoculis and Petrocephalus mbossou n. sp. Each species can be distinguished by a combination of characters, the most important of which are numbers of dorsal and anal fin rays, mouth width, eye size, number of upper jaw teeth and melanin markings. Electric signal waveform characteristics are useful for diagnosing a few of the species. The eleven Petrocephalus species of the Odzala assemblage appear to be reproductively isolated biological species based on genetic evidence we have gathered from the mitochondrial cytochrome b gene. Our study of Petrocephalus type material reveals that Petrocephalus guttatus was erroneously assigned to this genus; we now assign this species to Pollimyrus within the sister subfamily, Mormyrinae. Additionally, we provide a dichotomous key to the eleven Petrocephalus species of Odzala National Park.References
Agnèse, J.F. & Bigorne, R. (1992) Premières données sur les relations génétiques entre onze espèces ouest-africaines de Mormyridae (Teleostei, Osteichthyes). Revue d'Hydrobiologie tropicale, 25, 253–261.
Alves-Gomes, J.A. & Hopkins, C.D. (1997) Molecular insights into the phylogeny of mormyriform fishes and the evolution of their electric organs. Brain, Behavior and Evolution, 49, 324–351.
Arnegard, M.E., Bogdanowicz, S.M. & Hopkins, C.D. (2005) Multiple cases of striking genetic similarity between alternate electric fish signal morphs in sympatry. Evolution, 59, 324–343.
Arnegard, M.E. & Hopkins, C.D. (2003) Electric signal variation among seven blunt-snouted Brienomyrus species (Teleostei: Mormyridae) from a riverine species flock in Gabon, Central Africa. Environmental Biology of Fishes, 67, 321–339.
Bass, A.H. (1986) Electric organs revisited: evolution of a vertebrate communication and orientation organ. In: Bullock, T.H. & Heiligenberg, W. (Eds.) Electroreception. John Wiley and Sons, New York, pp. 13–70.
Bennett, M.V.L. (1970) Comparative physiology: Electric organs. Annual Review of Physiology, 32, 471–528.
Bigorne, R. & Paugy, D. (1991) Note sur la systématique des Petrocephalus (Teleostei, Mormyridae) d'Afrique de l'Ouest. Ichthyological Exploration of Freshwaters, 2, 1–30.
Boden, G., Teugels, G.G. & Hopkins, C.D. (1997) A systematic revision of the large-scaled Marcusenius with description of a new species from Cameroon (Teleostei; Osteoglossomorpha; Mormyridae). Journal of Natural History, 31, 1645–1682.
Boulenger, G.A. (1887) On new fishes from the lower Congo. Annals and Magazine of Natural History, 19, 148–149.
Boulenger, G.A. (1898) A revision of the genera and species of fishes of the family Mormyridae. Proceedings of the Zoological Society of London, 1898, 775–821.
Boulenger, G.A. (1899) Matériaux pour la faune du Congo. Zoologie––Série I. Poissons nouveaux du Congo. Quatrième Partie. Polyptères, Clupes, Mormyres, Characins. Annales du Musée du Congo, Zoologie, 1, 59–96.
Boulenger, G.A. (1902) Additions à la faune ichthyologique du bassin du Congo. Annales du Musée du Congo, Zoologie, 2, 19–57.
Boulenger, G.A. (1909–1916) Catalogue of the Freshwater Fishes of Africa in the British Museum (Natural History). Wheldon and Wesley, London, 4 volumes.
Boulenger, G.A. (1912) Poissons recueillis dans la région du Bas-Congo par le Dr. W. J. Ansorge. Annales du Musée du Congo, Zoologie, 2, 1–25.
Boulenger, G.A. (1913) Sur une petite collection de poissons recueillis dans l'Uélé par la mission dirigée par M. Hutereau. Revue de Zoologie Africaine, 2, 155–161.
Boulenger, G.A. (1914) Descriptions of three new fishes from South Cameroon. Annals and Magazine of Natural History, 14, 383–385.
Boulenger, G.A. (1915) Mission Stappers au Tanganyika-Moero. Diagnoses de poissons nouveaux. II. Mormyridés, Kneriidés, Characinidés, Cyprinidés, Siluridés. Revue de Zoologie Africaine, 4, 162–171.
Boulenger, G.A. (1920) Poissons recueillis au Congo Belge par l'expédition du Dr C. Christy. Matériaux pour la faune du Congo. Annales du Musée du Congo, Zoologie, 2, 1–38.
Bratton, B.O. & Kramer, B. (1988) Intraspecific variability of the pulse-type discharges of the African electric fishes, Pollimyrus isidori and Petrocephalus bovei (Mormyridae, Teleostei), and their dependence on water conductivity. Experimental Biology, 47, 227–238.
Crawford, J.D. & Hopkins, C.D. (1989) Detection of previously unrecognized mormyrid fish (Mormyrus subundulatus) by electric discharge characters. Cybium, 13, 319–326.
Cuvier, G. & Valenciennes, M.A. (1847) Histoire Naturelle des Poissons, Volume 20. Pitois, C., Paris, pp 472.
Daget, J., Gosse, J.P. & Thys van den Audenaerde, D.F.E. (1984) Cloffa: Check-list of the Freshwater Fishes of Africa, Volume 1. Paris, Tervuren, ORSTOM, MRAC, pp 412.
David, L. & Poll, M. (1937) Contribution à la faune ichthyologique du Congo belge. Annales du Musée du Congo, Zoologie, 3, 189–294.
Eschmeyer, W.N. & Fricke, R. (2010) Catalog of Fishes electronic version. Available from: http://research.calacademy.org/ichthyology/catalog/fishcatmain.asp (15 January 2010).
Feulner, P.G.D., Kirschbaum, F., Schugardt, C., Ketmaier, V. & Tiedemann, R. (2006) Electrophysiological and molecular genetic evidence for sympatrically occuring cryptic species in African weakly electric fishes (Teleostei: Mormyridae: Campylomormyrus). Molecular Phylogenetics and Evolution, 39, 198–208.
Fowler, H.W. (1936) Zoological results of the George Vanderbilt African Expedition of 1934. Part III– The fresh water fishes. Proceedings of The Academy of Natural Sciences of Philadelphia, 88, 243–335.
Gosse, J.P. (1984) Mormyridae. In: Daget, J., Gosse, J.P. & Thys van den Audenaerde, D.F.E. (Eds.) Cloffa: Catalogue of the Freshwater Fishes of Africa. ORSTOM, MRAC, Paris, Tervuren, pp. 63–124.
Günther, A. (1862) Eine neue art von Mormyrus. Archiv für Naturgeschichte, 28, 64.
Günther, A. (1866) Catalogue of the Fishes in the British Museum, volume 6. London, 368 pp.
Günther, A. (1867) New fishes from the Gaboon and Gold Coast. Annals and Magazine of Natural History, 20, 110–117.
Günther, A. (1896) Report of a collection of reptiles and fishes made by Miss M. H. Kingsley during her travels in the Ogowe River and in Old Calabar. Annals and Magazine of Natural History, 6, 261–285.
Harder, W. (1968) Zum Aufbau der epidermalen Sinnesorgane der Mormyridae (Mormyriformes, Teleostei). Zeitschrift für Zellforschung, 89, 212–224.
Harder, W. (2000) Mormyridae and other Osteoglossomorpha. World Biodiversity database, CD–ROM series, ETI BioInformatics, Amsterdam.
Hopkins, C.D. (1981) On the diversity of electric signals in a community of mormyrid electric fish in West Africa. American Zoologist, 21, 211–222.
Kramer, B. (1997) A field study of African elephantfish (Mormyridae, Teleostei): Electric organ discharges in Marcusenius macrolepidotus (Peters, 1852) and Petrocephalus catostoma (Günther, 1866) as related to sex. Journal of African Zoology, 111, 313–341.
Kramer, B. & van der Bank, F.H. (2000) The southern churchill, Petrocephalus wesselsi, a new species of mormyrid from South Africa defined by electric organ discharges, genetics, and morphology. Environmental Biology of Fishes, 59, 393–413.
Lavoué, S., Arnegard, M.E., Sullivan, J.P. & Hopkins, C.D. (2008) Petrocephalus of Odzala offer insights into evolutionary patterns of signal diversification in the Mormyridae, a family of weakly electrogenic fishes from Africa. Journal of Physiology–Paris, 102, 322–339.
Lavoué, S., Bigorne, R., Lecointre, G. & Agnèse, J.F. (2000) Phylogenetic relationships of mormyrid electric fishes (Mormyridae, Teleostei) inferred from cytochrome b sequences. Molecular Phylogenetics and Evolution, 14, 1–10.
Lavoué, S., Hopkins, C.D. & Kamdem Toham, A. (2004) The Petrocephalus (Pisces, Osteoglossomorpha, Mormyridae) of Gabon, Central Africa, with the description of a new species. Zoosystema, 26, 511–535.
Lissmann, H.W. (1958) On the function and evolution of electric organs in fish. Journal of Experimental Biology, 35, 156–191.
Marcusen, J. (1854) Vorläufige Mittheilung aus einer Abhandlung über die Familie des Mormyren. Bulletin de l'Académie des Sciences de St. Petersbourg, 12, 1–14.
Moller, P. (1995) Electric Fishes: History and Behavior. Chapman and Hall, London, 584 pp.
Moritz, T., Engelmann, J., Linsenmair, K.E. & von der Emde, G. (2009) The electric organ discharges of the Petrocephalus species (Teleostei: Mormyridae) of the Upper Volta System. Journal of Fish Biology, 74, 54–76.
Pellegrin, J. (1908) Sur une seconde collection de poissons recueillis par M. E. Haug à Ngomo. Bulletin de la Société Philomatique de Paris, 11, 184–190.
Pellegrin, J. (1924) Description de Mormyridés nouveaux récoltés au Congo belge par le Dr. Schouteden. Revue de Zoologie Africaine, 12, 1–8.
Pellegrin, J. (1928) Poissons du Chiloango et du Congo recueillis par l'expédition du Dr. H. Schouteden (1920–22). Annales du Musée du Congo, Zoologie, 3, 1–50.
Pezzanite, B. & Moller, P. (1998) A sexually dimorphic basal anal-fin ray expansion in the weakly discharging electric fish Gnathonemus petersii. Journal of Fish Biology, 53, 638–644.
Phillips, M.J., Delsuc, F. & Penny, D. (2004) Genome-scale phylogeny and the detection of systematic biases. Molecular Biology and Evolution, 21, 1455–1458.
Poll, M. (1939) Les poissons du Stanley Pool. Annales du Musée du Congo, Zoologie, 4, 1–60.
Poll, M. (1967) Contribution à la Faune Ichthyologique de l'Angola. Companhia de Diamantes de Angola (Diamang), Lisboa, pp 381.
Roberts, T.R. (1975) Geographical distribution of African freshwater fishes. Zoological Journal of the Linnean Society, 57, 249–319.
Sauvage, H.E. (1883) Descriptions de quelques poissons de la collection du Muséum d'Histoire Naturelle. Bulletin de la Société Philomatique de Paris, 7, 156–161.
Sauvage, H.E. (1884) Note sur des poissons de Franceville, Haut Ogôoué. Bulletin de la Société Zoologique de France, 9, 193–198.
Stamatakis, A. (2006) RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed models. Bioinformatics, 22, 2688–2690.
Steindachner, F. (1895) Die Fische Liberia's. Notes from the Leyden Museum, 16, 1–96.
Sullivan, J.P., Lavoué, S. & Hopkins, C.D. (2002) Discovery and phylogenetic analysis of a riverine species flock of African electric fishes (Mormyridae: Teleostei). Evolution, 56, 597–616.
Sullivan, J.P., Lavoué, S. & Hopkins, C.D. (2000) Molecular systematics of the African electric fishes (Mormyroidea: Teleostei) and a model for the evolution of their electric organs. Journal of Experimental Biology, 203, 665–683.
Taverne, L. (1969) Etude ostéologique des genres Boulengeromyrus Taverne et Géry, Genyomyrus Boulenger, Petrocephalus Marcusen (Pisces Mormyriformes). Annales du Musée Royal de l'Afrique Centrale, Sciences Zoologiques, 174, 1–85.
Taverne, L. (1972) Ostéologie des genres Mormyrus Linné, Mormyrops Müller, Hyperopisus Gill, Myomyrus Boulenger, Stomatorhinus Boulenger et Gymnarchus Cuvier. Considérations générales sur la systématique des Poissons de l'ordre des Mormyriformes. Annales du Musée Royal de l'Afrique Centrale, Sciences Zoologiques, 200, 1–194.
van der Bank, F.H. (1996) Inter- and intraspecific allozyme comparisons of mormyrids (Pisces, Mormyridae) from South Africa and Namibia, with reference to an undescribed species. Water SA, 22, 285–290.
Whitehead, P.J.P. & Greenwood, P.H. (1959) Mormyrid fishes of the genus Petrocephalus in Eastern Africa with a redescription of Petrocephalus gliroides (Vinciguerra). Revue de Zoologie et de Botanique Africaine, 60, 283–295.
Zakon, H.H., Lu, Y., Zwickl, D.J. & Hillis, D.M. (2006) Sodium channel genes and the evolution of diversity in communication signals of electric fishes: Convergent molecular evolution. Proceedings of the National Academy of Sciences of the United States of America, 103, 3675–3680.