Abstract
A new species of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha: Mormyridae: Petrocephalinae) is described from the Oubangui (Ubangi) River basin, the principal right-bank tributary of the Congo River. Petrocephalus leo sp. nov. is one of the most distinctive species of Petrocephalus as it combines (among other characteristics) the absence of electroreceptive rosettes on the head with a unique melanin pattern. Only four other species of Petrocephalus lack all electroreceptive rosettes: Petrocephalus microphthalmus, Petrocephalus haullevillii, Petrocephalus schoutedeni, and Petrocephalus zakoni. Petrocephalus leo sp. nov. can be distinguished from these four species in having a distinctive black mark at the base of the pectoral fins (versus absent in P. microphthalmus, P. haullevillii and P. schoutedeni) and no subdorsal black mark (versus present in P. zakoni). A phylogenetic analysis using mitochondrial cytochrome b gene sequences shows haplotypes of P. leo sp. nov. are distinct, but are unexpectedly nested within P. zakoni haplotypes, making this latter species paraphyletic. To investigate this conflict between morphology and mitochondrial cytochrome b, a nuclear marker, the first intron of the gene coding for the S7 ribosomal protein, was sequenced. The presence of four diagnostic indels between P. zakoni and P. leo sp. nov. sequences supports the reciprocal monophyly of these two species. This is the first reported case of conflict between morphology and mitochondrial phylogeny within the genus Petrocephalus. Finally, three species of Petrocephalus are reported for the first time from the Oubangui region bringing the total of Petrocephalus species in this region to 12.
References
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.
http://dx.doi.org/10.1080/00222939700770881Boulenger, G.A. (1887) On new fishes from the lower Congo. Annals and Magazine of Natural History, 19, 148–149.
http://dx.doi.org/10.1080/00222938709460214Boulenger, G.A. (1902) Additions la faune ichthyologique du bassin du Congo. Annales du Musée du Congo, Zoologie, 2, 19–57.
Boulenger, G.A. (1912) Poissons recueillis dans la région du Bas-Congo par M. le Dr. W. J. Ansorge. Annales du Musée du Congo Belge, Zoologie, 2, 1–28.
Boulenger, G.A. (1913) Sur une petite collection de poissons recueillis dans l'Uele par la mission dirigée par M. Hutereau. Revue de Zoologie Africaine, 2, 155–161.
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.
Chow, S. & Hazama, K. (1998) Universal PCR primers for S7 ribosomal protein gene introns in fish. Molecular Ecology, 7, 1247–1263.
Gosse, J.P. (1968) Les poissons du bassin de l'Ubangi. Document Zoologie du Musée royal de l'Afrique centrale, serie 13, 13, 1–56.
Harder, W. (1968) Zum Aufbau der epidermalen Sinnesorgane der Mormyridae (Mormyriformes, Teleostei). Zeitschrift für Zellforschung, 89, 212–224.
http://dx.doi.org/10.1007/BF00347294Harder, W. (2000) Mormyridae and other Osteoglossomorpha. ETI
Kramer, B., Bills, R., Skelton, P. & Wink, M. (2012) A critical revision of the churchill snoutfish, genus Petrocephalus Marcusen, 1854 (Actinopterygii: Teleostei: Mormyridae), from southern and eastern Africa, with the recognition of Petrocephalus tanensis, and the description of five new species. Journal of Natural History, 46, 2179–2258.
http://dx.doi.org/10.1080/00222933.2012.708452Lavoué, S. (2011) A new species of Petrocephalus Marcusen 1854 (Osteoglossomorpha: Mormyridae) from the Sanaga River basin, Cameroon. Zootaxa, 2934, 20–28.
Lavoué, S. (2012) Petrocephalus Marcusen, 1854 (Osteoglossomorpha: Mormyridae) of the Bangweulu-Mweru ecoregion (Luapula River system, Congo basin), with the description of a new species. Journal of Natural History, 46, 2159–2178.
http://dx.doi.org/10.1080/00222933.2012.708449Lavoué, 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.
http://dx.doi.org/10.1016/j.jphysparis.2008.10.003Lavoué, S., Sullivan, J.P. & Hopkins, C.D. (2003) Phylogenetic utility of the first two introns of the S7 ribosomal protein gene in African electric fishes (Mormyroidea: Teleostei) and congruence with other molecular markers. Biological Journal of the Linnean Society, 78, 273–292
http://dx.doi.org/10.1046/j.1095-8312.2003.00170.xLavoué, 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.
Lavoué, S., Miya, M., Arnegard, M.E., Sullivan, J.P., Hopkins, C.D. & Nishida, M. (2012) Comparable ages for the independent origins of electrogenesis in African and South American weakly electric fishes. PLoS ONE, 7, e36287.
http://dx.doi.org/10.1371/journal.pone.0036287Lavoué, S. & Sullivan, J.P. (2014) Petrocephalus boboto and Petrocephalus arnegardi, two new species of African electric fish (Osteoglossomorpha, Mormyridae) from the Congo River basin. Zookeys 400, 43–65.
http://dx.doi.org/10.3897/zookeys.400.6743Lavoué, S., Sullivan, J.P. & Arnegard, M.E. (2010) African weakly electric fishes of the genus Petrocephalus (Osteoglossomorpha: Mormyridae) of Odzala National Park, Republic of the Congo (Lekoli River, Congo River basin) with description of five new species. Zootaxa, 2600, 1–52.
Maddison, W.P. & Maddison, D.R. (2000) MacClade: Analysis of Phylogeny and Character Evolution. Sinauer Associates, Sunderland, MA.
Paugy, D., Zaiss, R. & Troubat, J.J. (2008) FAUNAFRI (version 05/2015). World Wide Web electronic publication, http://www.poissons-afrique.ird.fr/faunafri/
Pellegrin, J. (1908) Sur une seconde collection de poissons recueillis par M. E. Haug Ngomo. Bulletin de la Société Philomatique de Paris, 11, 184–190.
Pellegrin, J. (1920) Poissons de l'Ouham et de l'Oubanghi recueillis par M. Baudon. Description de deux cyprinidés nouveaux. Bulletin de la Société Zoologique de France, 45, 245–248.
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.
http://dx.doi.org/10.1111/j.1095-8649.1998.tb01007.xPoll, M. (1954) Poissons de forêt des environs de Yangambi (Stanleyville) recueillis par A. Hulot. Annales du Musée Royal du Congo Belge, Série I, 1, 56–68.
Sauvage, H.E. (1879) Notice sur la faune ichthyologique de l'Ogooué. Bulletin de la Société Philomatique de Paris, 7, 90–103.
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.
Silvestro, D. & Michalak, I. (2012) raxmlGUI: a graphical front-end for RAxML. Organisms Diversity & Evolution, 12, 335–337.
http://dx.doi.org/10.1007/s13127-011-0056-0Stamatakis, A. (2006) RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed models. Bioinformatics, 22, 2688–2690.
http://dx.doi.org/10.1093/bioinformatics/btl446Sullivan, J.P. & Lavoué, S. (2016) Mormyridae—African weakly electric fishes Scratchpad. World Wide Web electronic publication, http://mormyrids.myspecies.info/en.
Sullivan, J.P., Lavoué, S., Arnegard, M.E. & Hopkins, C.D. (2004) AFLPs resolve phylogeny and reveal mitochondrial introgression within a species flock of African electric fish (Mormyroidea: Teleostei). Evolution, 58, 825–841.
http://dx.doi.org/10.1111/j.0014-3820.2004.tb00415.xSullivan, J.P., Lavoué, S. & Hopkins, C.D. (2016) Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa. ZooKeys, 561, 117–150.
http://dx.doi.org/10.3897/zookeys.561.7137Sullivan, 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.
http://dx.doi.org/10.1554/0014-3820(2002)056[0597:DAPAOA]2.0.CO;2Sullivan, 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. (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.
Thieme, M.L., Abell, R., Stiassny, M.L.J., Skelton, P., Burgess, N., Lehner, B., Dinerstein, E., Olson, D., Teugels, G.G. & Kamdem-Toham, A. (2005) Freshwater ecoregions of Africa and Madagascar: a conservation assessment. Island Press, Washington, 483 pp.
Vos, P., Hogers, R., Bleekers, M., Reijans, M., van de Lee, T., Hornes, M., Frijters, A., Pot, J., Peleman, J., Kuiper, M. & Zabeau, M. (1995) AFLP: a new technique for DNA fingerprinting. Nucleic Acids Research, 23, 4407–4414.
http://dx.doi.org/10.1093/nar/23.21.4407