@article {668, title = {Length-weight relationships and condition factors of Mormyridae species in the Niger River: implications for conservation and management}, journal = {Limnology and Freshwater Biology }, volume = {2025}, year = {2025}, month = {Jan-01-2025}, pages = {215-221}, abstract = {

The length-weight relationship and condition factor of the ten most abundant Mormyridae species in the Niger River at Niamey were examined from August to November 2023. The species assessed were\ Mormyrus rume,\ Campylomormyrus tamandua,\ Pollimyrus isidori,\ Brienomyrus niger,\ Hyperopisus bebe, Mormyrus macrophthalmus,\ Mormyrops anguilloides,\ Brevimyrus niger,\ Mormyrops oudoti,\ Cyphomyrus Psittacus, and\ Marcusenius cyprinoides. Analysis of their length-weight relationships revealed \“b\” values ranging from 2.08 to 2.87, suggesting negative allometric growth across all species. Condition factor (k) values varied from 1.22 \± 0.31 for\ H. bebe\ to 10.48 \± 2.83 for\ M. cyprinoides, with no significant differences in average condition factors among the species. These findings highlight the potential vulnerability of Mormyridae species to environmental changes and anthropogenic pressures, emphasizing the need for targeted conservation measures. The results underscore the importance of sustainable fisheries management practices to preserve biodiversity and ensure the long-term productivity of the Niger River ecosystem. The observed negative allometric growth patterns indicate that environmental conditions may be suboptimal for these species, potentially due to factors such as habitat degradation, water quality issues, or overfishing. Addressing these challenges through habitat restoration and regulatory measures could enhance the resilience of fish populations and support sustainable fisheries.

}, keywords = {condition factor, length-weight analysis, Mormyridae, sustainable fisheries management, the Niger River}, issn = {2658-3518}, doi = {10.31951/2658-3518-2025-a-2-215}, url = {https://doi.org/10.31951/2658-3518-2025-a-2-215}, author = {Souley, S.M.N. and Harouna, M. and Ado, M.I. and Youssoufa, I.} } @article {620, title = {The Complete Genome Sequences of 38 Species of Elephantfishes (Mormyridae, Osteoglossiformes)}, year = {2022}, month = {Nov-21-2022}, abstract = {

We present the complete genome sequences of 38 species of elephantfishes from 20 genera. Illumina sequencing was performed on genetic material from single wild-caught individuals. The reads were assembled using a de novo method followed by a finishing step. The raw and assembled data is publicly available via Genbank.

}, issn = {2687-7945}, doi = {10.56179/001c.56077}, url = {http://dx.doi.org/10.56179/001c.56077}, author = {Rose Peterson and John P Sullivan and Stacy Pirro} } @article {602, title = {Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua ♂ {\texttimes} C. compressirostris ♀) are fertile}, journal = {Journal of Comparative Physiology A}, volume = {206}, year = {2020}, month = {Jan-07-2020}, pages = {571 - 585}, abstract = {

Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids between Campylomormyrus tamandua ♂ \× C. compressirostris ♀ were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12\–13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8\%. Eggs started to hatch 70\–72 h after fertilization, average hatching rate was 95.6\%. Average mortality rate during embryonic development amounted to 2.3\%. Average malformation rate during the free embryonic stage was 27.7\%. Exog- enous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically.

}, issn = {0340-7594}, doi = {10.1007/s00359-020-01425-7}, url = {http://link.springer.com/10.1007/s00359-020-01425-7}, author = {Korniienko, Yevheniia and Nguyen, Linh and Baumgartner, Stephanie and Vater, Marianne and Ralph Tiedemann and Kirschbaum, Frank} } @article {587, title = {Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences}, journal = {Evolutionary Ecology}, year = {2020}, month = {Apr-04-2021}, abstract = {

Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype\–environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated.

}, issn = {0269-7653}, doi = {10.1007/s10682-020-10043-3}, url = {http://link.springer.com/10.1007/s10682-020-10043-3}, author = {Amen, Rahma and Nagel, Rebecca and Hedt, Maximilian and Kirschbaum, Frank and Ralph Tiedemann} } @article {559, title = {Electric pulse characteristics can enable species recognition in African weakly electric fish species}, journal = {Scientific Reports}, volume = {8}, year = {2018}, month = {Jan-12-2018}, abstract = {

Communication is key to a wide variety of animal behaviours and multiple modalities are often involved in this exchange of information from sender to receiver. The communication of African weakly electric fish, however, is thought to be predominantly unimodal and is mediated by their electric sense, in which species-specific electric organ discharges (EODs) are generated in a context-dependent and thus variable sequence of pulse intervals (SPI). While the primary function of the electric sense is considered to be electrolocation, both of its components likely carry information regarding identity of the sender. However, a clear understanding of their contribution to species recognition is incomplete. We therefore analysed these two electrocommunication components (EOD waveform and SPI statistics) in two sympatric mormyrid Campylomormyrus species. In a set of five playback conditions, we further investigated which components may drive interspecific recognition and discrimination. While we found that both electrocommunication components are species-specific, the cues necessary for species recognition differ between the two species studied. While the EOD waveform and SPI were both necessary and sufficient for species recognition in C. compressirostris males, C. tamandua males apparently utilize other, non-electric modalities. Mapped onto a recent phylogeny, our results suggest that discrimination by electric cues alone may be an apomorphic trait evolved during a recent radiation in this taxon.

}, doi = {10.1038/s41598-018-29132-z}, url = {http://www.nature.com/articles/s41598-018-29132-z}, author = {Nagel, Rebecca and Frank Kirschbaum and Hofmann, Volker and Engelmann, Jacob and Ralph Tiedemann} } @article {499, title = {Species delimitation and phylogenetic relationships in a genus of African weakly-electric fishes (Osteoglossiformes, Mormyridae, Campylomormyrus)}, journal = {Molecular Phylogenetics and Evolution}, year = {2016}, month = {Jan-04-2016}, abstract = {

African weakly-electric fishes (Mormyridae) are able to communicate through species-specific electric signals; this feature might have favoured the evolutionary radiation observed in this family (over 200 species) by acting as an effective pre-zygotic isolation mechanism. In the present study we used mitochondrial (cytb) and nuclear (rps7, scn4aa) markers in order to reconstruct a species-phylogeny and identify species boundaries for the genus Campylomormyrus, by applying inference methods based on the multispecies coalescent model. Additionally, we employed 16 microsatellite markers, landmark-based morphometric measurements, and electro-physiological analyses as independent lines of evidence to the results obtained from the sequence data. The results show that groups that are morphologically different are also significantly divergent at the genetic level, whereas morphologically similar groups, displaying dissimilar electric signals, do not show enough genetic diversity to be considered separate species. Furthermore, the data confirm the presence of a yet undescribed species within the genus Campylomormyrus.

}, keywords = {Campylomormyrus, Geometric morphometrics, Microsatellites, Mormyridae, Multispecies-coalescent, Species-delimitation}, issn = {10557903}, doi = {10.1016/j.ympev.2016.04.035}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1055790316300781}, author = {Lamanna, Francesco and Frank Kirschbaum and Ernst, Anja R.R. and Philine G.D. Feulner and Victor Mamonekene and Paul, Christiane and Ralph Tiedemann} } @article {cite-key, title = {Description of a new species of Mormyrus}, journal = {Proceedings of the General Meetings for Scientific Business of the Zoological Society of London}, volume = {1864 (pt 1)}, year = {1864}, month = {July}, pages = {22 (Pl. 2)}, keywords = {Mormyrus petersii}, author = {G{\"u}nther, Albert C. L. G.} } @article {172, title = {Description of a new species of Mormyrus}, journal = {Annals and Magazine of Natural History (Series 6)}, volume = {6}, number = {32}, year = {1890}, month = {08/1890}, pages = {193}, url = {http://biostor.org/reference/66397}, author = {George A. Boulenger} } @article {608, title = {A revision of the genera and species of fishes of the family Mormyridae}, journal = {Proceedings of the General Meetings for Scientific Business of the Zoological Society of London}, volume = {1898}, number = {Part 4}, year = {1899}, pages = {775-821}, url = {http://www.biodiversitylibrary.org/item/97095$\#$page/919/mode/1up}, author = {George A. Boulenger} } @inbook {121, title = {Catalogue of the Fresh-Water Fishes of Africa in the British Museum (Natural History)}, booktitle = {Catalogue of the Fresh-Water Fishes of Africa in the British Museum (Natural History)}, volume = {I}, year = {1909}, pages = {29-145}, publisher = {British Museum (Natural History)}, organization = {British Museum (Natural History)}, address = {London}, url = {https://biodiversitylibrary.org/page/37889609}, author = {George A. Boulenger} } @article {260, title = {Contribution {\`a} la faune ichthyologique du Congo Belge: Collections du Dr. H. Schouteden (1924-1926) et d{\textquoteright}autres r{\'e}colteurs}, journal = {Annales du Mus{\'e}e du Congo Belge (S{\'e}rie 1)}, volume = {3 (fasc. 5)}, year = {1937}, month = {05/1937}, pages = {189{\textendash}294}, author = {David, L. and Poll, M.} } @article {832, title = {Les poissons du bassin du Tchad et du bassin adjacent du Mayo Kebbi {\'e}tude syst{\'e}matique et biologique}, year = {1964}, pages = {1{\textendash}483}, publisher = {ORSTOM}, address = {Paris}, url = {http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_2/memoires/19994.pdf}, author = {Blache, J.} } @article {144, title = {Les Poissons du Stanley-Pool}, journal = {Annales du Mus{\'e}e du Congo belge. C.{\textendash}Zoologie S{\'e}rie I.}, volume = {4}, number = {1}, year = {1939}, month = {12/1939}, pages = {1-60}, chapter = {1}, author = {Poll, M.} } @article {214, title = {An ecological and systematics survey of fishes in the rapids of the Lower Za{\"\i}re or Congo River}, journal = {Bulletin of the Museum of Comparative Zoology}, volume = {147}, number = {6}, year = {1976}, month = {02/1976}, pages = {239{\textendash}317}, url = {http://biodiversitylibrary.org/page/4276443}, author = {Roberts, T.R. and Stewart, D.J.} } @article {267, title = {Le genre Campylomormyrus Bleeker, 1874, {\'e}tude systematique et description d{\textquoteright}une espece nouvelle (Pisces, Mormyridae)}, journal = {Bulletin de l{\textquoteright}Institut Royal des Sciences de Belgique Biologie}, volume = {54}, number = {5}, year = {1982}, month = {08/1982}, pages = {1{\textendash}34, Pls. 1{\textendash}13}, author = {Poll, M. and Gosse, J.-P. and Orts, S.} } @article {831, title = {Aspects of the reproductive biology of Hippopotamyrus pictus from Lake Kainji, with notes on four other mormyrid species}, journal = {Journal of Fish Biology}, volume = {11}, number = {5}, year = {1977}, pages = {437{\textendash}445}, abstract = {

A method is descrihed for the assessment of fecundity in in mormyrrd fish. In all species examined a tri-modal egg size distribution was found in the mature pre-spawning ovary. These modes represented one oocyte and two ova components. The significance of the presence of two sizes of ovum is discussed in relation to breeding periodicity in Hippopotamyrus pictus. Size and age at first maturity are estimated for this species. The probable effects of the formation of the lake on the breeding behaviour of mormyrids is discussed.

}, url = {http://onlinelibrary.wiley.com/store/10.1111/j.1095-8649.1977.tb04138.x/asset/j.1095-8649.1977.tb04138.x.pdf?v=1\&t=hqzjgrlk\&s=80a89cbded91f381ca05b0ee20d62e74d4487e99}, author = {Blake, B.F.} } @inbook {179, title = {Mormyridae}, booktitle = {Faune des poissons d{\textquoteright}eaux douces et saum{\^a}tres de l{\textquoteright}Afrique de l{\textquoteright}Ouest = The fresh and brackish water fishes of West Africa}, series = {Faune tropicale 28}, year = {1990}, pages = {122-184}, publisher = {ORSTOM, MRAC}, organization = {ORSTOM, MRAC}, address = {Paris, Tervuren (Belgium)}, url = {http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/Fau_trop/34060.pdf}, author = {Bigorne, R.}, editor = {L{\'e}v{\^e}que, C. and Paugy, D. and Teugels, G.G.} } @inbook {158, title = {Mormyridae}, booktitle = {Faune des poissons d{\textquoteright}eaux douces et saum{\^a}tres de l{\textquoteright}Afrique de l{\textquoteright}Ouest}, volume = {1}, year = {2003}, pages = {154-222}, publisher = {IRD/MNHN/MRAC}, organization = {IRD/MNHN/MRAC}, url = {http://www.ird.fr/editions/catalogue/ouvrage.php?livre=409}, author = {Bigorne, R.} } @book {159, title = {The Mormyridae and other Osteoglossomorpha (CD-ROM)}, series = {World Biodiversity Database, CD-ROM Series}, volume = {2000}, year = {2000}, publisher = {Springer Verlag, ETI-UNESCO}, organization = {Springer Verlag, ETI-UNESCO}, address = {New York}, issn = {Hyb: 3-540-14811-6}, url = {https://www.amazon.com/Mormyridae-Osteoglossomorpha-Biodiversity-Database-CD-ROM/dp/3540148116}, author = {Harder, W.} } @article {889, title = {Adaptive radiation in African weakly electric fish (Teleostei: Mormyridae: Campylomormyrus): a combined molecular and morphological approach}, journal = {Journal of Evolutionary Biology}, volume = {20}, year = {2007}, month = {01/2007}, pages = {403 - 414}, abstract = {

We combined multiple molecular markers and geometric morphometrics to revise the current taxonomy and to build a phylogenetic hypothesis for the African weakly electric fish genus Campylomormyrus. Genetic data (2039 bp DNA sequence of mitochondrial cytochrome b and nuclear S7 genes) on 106 specimens support the existence of at least six species occurring in sympatry. We were able to further confirm these species by microsatellite analysis at 16 unlinked nuclear loci and landmark-based morphometrics. We assigned them to nominal taxa by comparisons to type specimens of all Campylomormyrus species recognized so far. Additionally, we showed that the shape of the elongated trunk-like snout is the major source of morphological differentiation among them. This finding suggests that the radiation of this speciose genus might have been driven by adaptation to different food sources.

}, issn = {1420-9101}, doi = {10.1111/j.1420-9101.2006.01181.x}, author = {Philine G.D. Feulner and Frank Kirschbaum and Victor Mamonekene and Ketmaier, V. and Ralph Tiedemann} } @article {167, title = {Electrophysiological and molecular genetic evidence for sympatrically occuring cryptic species in African weakly electric fishes (Teleostei: Mormyridae: Campylomormyrus)}, journal = {Biology Letters Evolutionary Biology}, volume = {39}, year = {2006}, pages = {198-208}, abstract = {

For two sympatric species of African weakly electric Wsh, Campylomormyrus tamandua and Campylomormyrus numenius, we moni- tored ontogenetic diVerentiation in electric organ discharge (EOD) and established a molecular phylogeny, based on 2222 bp from cyto- chrome b, the S7 ribosomal protein gene, and four Xanking regions of unlinked microsatellite loci. In C. tamandua, there is one common EOD type, regardless of age and sex, whereas in C. numenius we were able to identify three diVerent male adult EOD waveform types, which emerged from a single common EOD observed in juveniles. Two of these EOD types formed well supported clades in our phyloge- netic analysis. In an independent line of evidence, we were able to aYrm the classiWcation into three groups by microsatellite data. The correct assignment and the high pairwise FST values support our hypothesis that these groups are reproductively isolated. We propose that in C. numenius there are cryptic species, hidden behind similar and, at least as juveniles, identical morphs.

}, doi = {10.1016/j.ympev.2005.09.008}, author = {Philine G.D. Feulner and Frank Kirschbaum and Victor Mamonekene and Ketmaier, V. and Ralph Tiedemann} } @article {891, title = {Electrifying love: electric fish use species-specific discharge for mate recognition}, journal = {Biology Letters}, volume = {520927419392041142915996351451455587020220191}, year = {2009}, month = {04/2009}, pages = {225 - 228}, abstract = {

A unique evolutionary specialization of African weakly electric fish (Mormyridae) is their ability to produce and perceive electric signals. Mormyrids use their electric organs discharge (EOD) for electrolocation and electrocommunication. Here we discuss the adaptive significance of the EOD in foraging (electric prey detec- tion) in light of recent results demonstrating that mormyrid fish mate assortatively according to EOD waveform characteristics (electric mate choice). Therefore the EOD as a single trait pleio- tropically combines natural divergent selection and reproductive isolation. Consequently we postulate the EOD as a \“magic trait\” promoting the diversification of African weakly electric fish.

}, issn = {0179-1613}, doi = {10.1098/rsbl.2008.0566}, author = {Philine G.D. Feulner and Plath, M. and Engelmann, J. and Frank Kirschbaum and Ralph Tiedemann} } @article {890, title = {Adaptive radiation in the Congo River: An ecological speciation scenario for African weakly electric fish (Teleostei; Mormyridae; Campylomormyrus)}, journal = {Journal of Physiology-Paris}, volume = {102}, year = {2008}, month = {7/2008}, pages = {340 - 346}, abstract = {

he ultimate aim of this study is to better understand the diversification of African weakly electric fish in the Congo River. Based on a robust phylogenetic hypothesis we examined the radiation within the mor- myrid genus Campylomormyrus. Morphological traits relevant for the divergence between the identified species were detected. Among them, the variation in the shape of the trunk-like elongated snout sug- gested the presence of different trophic specializations. Furthermore, the chosen model taxon, the genus Campylomormyrus, exhibits a wide diversity of electric organ discharge (EOD) waveforms. A comparison of EOD waveform types and phylogenetic relationships showed major differences in EOD between closely related species. This indicates that the EOD might function as a reproductive isolation mechanism. In con- clusion, we provide a plausible scenario of an adaptive radiation triggered by sexual selection and assor- tative mating based on EOD characteristics, but caused by a divergent selection on the feeding apparatus. These findings point towards an adaptive radiation of at least some Campylomormyrus species occurring in the Lower Congo River.

}, issn = {09284257}, doi = {10.1016/j.jphysparis.2008.10.002}, author = {Philine G.D. Feulner and Frank Kirschbaum and Ralph Tiedemann} }