@article {669, title = {High-frequency electrical tuning and linear filter properties of Knollenorgan electroreceptors of mormyrid electric fish}, journal = {The Journal of Physiology}, year = {2025}, month = {Jun-15-2025}, pages = {1-22}, chapter = {1}, abstract = {

Electrical tuning allows auditory, vestibular, and electrosensory receptor cells to filter sensory signals and selectively transmit specific stimulus frequencies. In auditory hair cells, electrical tuning results from membrane potential resonance produced by voltage-gated Ca and K(Ca) channels, with variable kinetics that generate different tuning properties. Such resonance has been observed only up to \∼1 kHz, however. Additionally, in most species that employ electrical tuning, hearing is constrained to this relatively low-frequency range, raising the question of whether electrical tuning can extend to higher frequencies. Here we investigated this possibility by studying tuning and transduction properties of Knollenorgans, a class of tuberous electroreceptors of mormyrid electric fish. These organs, which generate spike-like receptor potentials, detect species-specific electric organ discharges (EODs). To test whether fish with brief EODs had correspondingly high-frequency electrical tuning, we recorded tuning curves from Knollenorgans of three species, Brevimyrus niger, Gnathonemus petersii, and Pollimyrus adspersus, which have EODs with spectral components exceeding 5 kHz. All species had receptors tuned to a range of frequencies tiling the species-specific EOD spectrum, with best frequencies extending beyond 10 kHz in P. adspersus. We also computed the impulse response of each Knollenorgan by reverse-correlating spikes elicited by white noise stimuli. After incorporation of a spike threshold non-linearity, convolving the impulse response with arbitrary stimulus waveforms successfully predicted spike patterns experimentally evoked by these inputs. These analyses demonstrate that differential electrical tuning properties of Knollenorgans produce distinct, well-timed spike responses that reliably encode time-varying electrical signals at frequencies up to 20 kHz. imageKey points Knollenorgans, among the tuberous electroreceptors of mormyrid electric fish, are modified hair cells that transduce electrical signals into spike-like receptor potentials. Knollenorgans in three species of mormyrids are tuned to frequencies matched to the frequencies present in the species-typical electric organ discharges, suiting them for electric communication. The frequency of highest sensitivity of Knollenorgans can extend well beyond 10 kHz, far exceeding the limit for electrical tuning mechanisms estimated from mechanosensitive hair cells. The timing and probability of spiking by Knollenorgans are accurately predicted by a model composed of linear filtering followed by non-linear rectification and spike thresholding. Differential filtering by different Knollenorgans produces distinct outputs to the same input, with high-tuned receptors effectively transmitting well-timed spikes, on a microsecond time scale, in response to electrical stimuli up to 20 kHz.

}, issn = {0022-3751, 1469-7793}, doi = {10.1113/jp288299}, url = {https://doi.org/10.1113/jp288299}, author = {Raman, Indira M. and Hopkins, Carl D.} } @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 {662, title = {Morphometric synthesis of Pollimyrus (Teleostei, Mormyridae) with the description of four new species}, journal = {Journal of Fish Biology}, volume = {2024}, year = {2024}, month = {Nov-24-2024}, pages = {1-47}, abstract = {

Mormyridae, a species-rich family endemic to Africa, remains taxonomically understudied. This has been the case for the genus Pollimyrus Taverne, 1971, which hinders further understanding of the distribution, ecology, and conservation of its species. Therefore, an in-depth morphometric comparison of all currently valid species is carried out using most of the available type specimens. Species delineations were re-evaluated, and four species new to science described: Pollimyrus ibalazambai sp. nov. (the Luki River, the Democratic Republic of the Congo), Pollimyrus krameri sp. nov. (the Lugenda River, Mozambique), Pollimyrus vanneeri sp. nov. (the Kouilou-Niari River, the Republic of the Congo), and Pollimyrus weyli sp. nov. (the Buzi River, Mozambique). In this study, Pollimyrus guttatus is confirmed to belong to Pollimyrus, whereas Pollimyrus eburneensis and Cyphomyrus plagiostoma seem more similar to species allocated to other genera. No or only little morphological differences were found between the type series of several species, which could indicate the need for synonymization of these species (Pollimyrus cuandoensis with Pollimyrus marianne and Pollimyrus nigripinnis with Pollimyrus pulverulentus). As such 20 species are currently morphologically identifiable in the genus Pollimyrus. The present study highlights the critical need for further synthetic efforts and new collecting efforts across Africa for this and other Mormyridae genera.

}, keywords = {morphology, Pollimyrus ibalazambai sp. nov., Pollimyrus krameri sp. nov., Pollimyrus vanneeri sp. nov., Pollimyrus weyli sp. nov., Taxonomy}, issn = {0022-1112, 1095-8649}, doi = {10.1111/jfb.15983}, url = {http://dx.doi.org/10.1111/jfb.15983}, author = {Dierickx, Katrien and Wamuini Lunkayilakio, Soleil and Bills, Roger and Vreven, Emmanuel} } @article {646, title = {Sur quelques poissons du Sud de la C{\^o}te d{\textquoteright}Ivoire}, journal = {Revue Suisse de Zoologie}, volume = {77}, year = {1970}, pages = {801-806}, chapter = {801}, abstract = {

La faune des poissons d\’eau douce de C\ôte d\’Ivoire est loin d\‘\être parfaitement connue puisque la pr\ésente collection permet d\’ajouter cinq esp\èces \à la liste de celles d\éj\à signal\ées de ce pays. Ces esp\èces sont: Marcusenius kingsleyae, Lapidarchus adonis, Notoglaizidium walkeri, Mjrophis plumbeus et Poropanchax nianni. Du bassin de l\&$\#$39;Agn\ébi sont signal\ées pour la premi\ère fois : Marcusenius kingsleyae, Notoglanidiuin walkeri, Afronandus sheljiukhoi et Pelmatochromis ansorgii. Le nombre des esp\èces continentales actuellement connues de ce bassin passe donc de 29 \à 33. Du Banco est signal\é pour la premi\ère fois Marcusenius kingsleyae; le nombre des esp\èces de ce cours d\‘eau passe donc de 11 \à 12.

}, url = {https://www.documentation.ird.fr/hor/fdi:04701}, author = {Daget, J. and de Rham, P.} } @inbook {633, title = {Exploration du Parc National de l{\textquoteright}Upemba Mission G.F. De Witte, Fascicule 73 Poissons}, booktitle = {Exploration du Parc National de l{\textquoteright}Upemba Mission G.F. De Witte}, volume = {73}, year = {1976}, publisher = {Fondation Pour Favoriser Les Recherches Scientifiques en Afrique}, organization = {Fondation Pour Favoriser Les Recherches Scientifiques en Afrique}, address = {Brussels}, author = {Poll, M.} } @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 {610, title = {Ost{\'e}ologie des Genres Marcusenius Gill, Hippopotamyrus Pappenheim, Cyphomyrus Myers, Pollimyrus Taverne et Brienomyrus Taverne (Pisces Mormyriformes)}, journal = {Annales du Mus{\'e}e royal de l{\textquoteright}Afrique centrale, Sciences Zoologiques}, volume = {188}, year = {1971}, pages = {144}, url = {https://www.nhbs.com/osteologie-des-genres-marcusenius-gill-hippopotamyrus-pappenheim-cyphomyrus-myers-pollimyrus-taverne-et-brienomyrus-taverne-pisces-mormyriformes-book}, author = {Taverne, L.} } @article {585, title = {Sound Production and Reproductive Ecology of Strongly Acoustic Fish in Africa: Pollimyrus isidori, Mormyridae}, journal = {Behaviour}, volume = {134}, year = {1997}, month = {Jan-01-1997}, pages = {677 - 725}, abstract = {

We have studied the reproductive ecology and bioacoustic signals of weakly electric mormyrid fish in Africa in order to discover the natural conditions under which acoustic signals are used and to gain insight into the evolution of their acoustic behaviour and hearing. Pollimyrus\ isidori migrated from a tributary of the Niger River (Mali) into a shallow (2- 3 m) flood plain during the onset of the flooding seasons (August, 1991 and 1994). The\ fish were fully primed for reproduction upon entering the plain, females were significantly larger than males, and the sex ratio was skewed toward males (about 2 males per female). Males established territories (d \≈ 1 m) within the roots of floating rafts of grasses, about 0.5 m below the water surface. Males produced conspicuous acoustic displays consisting of Grunts and Moans during the night (130 dB peak re 1 \μLPaat approximately 10 cm). These sounds had a fundamental of 340 Hz, but the band-width of the grunt extended to over 3 kHz. Experiments at the field site with captive animals showed that male sound production was stimulated by the presence of conspecific females. The P. isidori repertoire included 3 additional sounds. Analysis of environmental noise showed that these communication sounds fall within a distinct spectral window, thereby minimizing potential interference from other aquatic animals and abiotic noise sources. Waveform analyses showed that the sounds remained coherent over short distances (0.5 m) but lost amplitude more rapidly than would be predicted in a deep water free-field.

}, doi = {10.1163/156853997X00034}, url = {https://brill.com/view/journals/beh/134/9-10/article-p677_3.xmlhttps://data.brill.com/files/journals/1568539x_134_09-10_s003_text.pdf}, author = {Benech, Vincent and Jacob, Philippe and Crawford, John D.} } @article {567, title = {Poissons de Kapanga (Katanga)}, journal = {Revue de Zoologie et de Botanique Africaines }, volume = {27}, year = {1935}, month = {25 Sep 1935}, pages = {293-294}, chapter = {293}, author = {David, L.} } @article {547, title = {New insights into the molecular phylogeny and taxonomy of mormyrids (Osteoglossiformes, Actinopterygii) in northern East Africa}, journal = {Journal of Zoological Systematics and Evolutionary Research}, year = {2017}, month = {Feb-09-2019}, abstract = {

Based on morphological data and analysis of mitochondrial cytochrome b gene and nuclear (S7 intron 1) DNA sequences, the phylogenetic relationships of all Pollimyrus species known from the Omo-Turkana enclosed basin and Nile system below the Murchison Falls were solved. A mormyrid \“Pollimyrus\” petherici is distantly related to all other studied Pollimyrus species and clusters together with Cyphomyrus species forming with the later a monophyletic group. Moreover, the West African (but not the Congo River) populations of Cyphomyrus psittacus, the type species of the genus, seem to be conspecific to C. petherici. That is, the range of the genus Cyphomyrus is extended toward the Nile and Omo-Turkana basins. This genus belongs to the large clade widely distributed in sub-Saharian Africa and characterized by the presence of a chin appendage. Significance of this character for mormyrid phylogeny is discussed. Two distinct lineages of Pollimyrus occurring sympatrically in the White Nile tributaries and previously reported as the light and dark forms of Pollimyrus isidori together with five other congeneric species studied form a monophyletic group. The light form apparently represents P. isidori distributed in the Nile system downstream of the Murchison Falls and West Africa; the dark-colored form (designated as Pollimyrus \“D\”) represents a distinct phylogenetic lineage inhabiting both the Omo-Turkana and the White Nile basin. Morphological and ecological data suggest that this form may be conspecific to East African Pollimyrus nigricans or most probably represents a new species.

}, doi = {10.1111/jzs.12186}, url = {http://doi.wiley.com/10.1111/jzs.12186}, author = {Levin, Boris A. and Alexander Golubtsov} } @article {463, title = {On a collection of fishes from the Lake Ngami Basin, Bechuanaland}, journal = {Transactions of the Zoological Society of London}, volume = {18}, year = {1911}, pages = {399-431}, chapter = {399}, url = {http://biodiversitylibrary.org/page/31647095}, author = {George A. Boulenger} } @article {458, title = {More new fishes from the Kasai District of the Belgian Congo}, journal = {American Museum Novitates}, volume = {723}, year = {1934}, month = {8 May 1934}, pages = {1{\textendash}6}, type = {taxonomic report}, chapter = {1}, abstract = {

A number of small fishes collected in 1932 by Callewaert, at Luluabourg in the Kasai District of the Belgian Congo, were overlooked when the remainder of his collection made at that time was studied and reported on. Their examination, just completed, adds 20 forms to the 42 from the locality previously enumerated in The American Museum of Natural History\&$\#$39;s collections: namely, 5 mormyrids, 4 characins, 2 cyprinids of which 1 is a Barbus, 5 catfishes, 3 cichlids, 1 Anabas. Our complete collections from the locality now number, 62 species: in percentages, 21 mormyrids, 14 1/2 characins, 35 catfishes, 5 Barbus, 6 1/2\  cichlids, and 18 otherwise distributed; characins, catfishes and cichlids being somewhat closer to figures for the Congo than were those reported for the incomplete Luluabourg collections in 1933. The following new species are included: Marcusenius maculipinnis, Heterobranchus platycephaius, Euchilichthys boulengeri, and Steatocranus nelongatus.

}, issn = { 0003-0082}, doi = { http://digitallibrary.amnh.org/dspace/bitstream/2246/4609/1//v2/dspace/ingest/pdfSource/nov/N0723.pdf}, url = {http://bionames.org/references/bae56de4b8deb2370183321f00d6e687}, author = {Nichols, J.T. and La Monte, F.R. and Callewaert, R.} } @article {446, title = {Note sur la syst{\'e}matique des poissons Mormyriformes. Le probl{\`e}me des genres Gnathonemus Gill, Marcusenius Gill, Hippopotamyrus Pappenheim, Cyphomyrus Myers et les nouveaux genres Pollimyrus et Brienomyrus}, journal = {Revue de Zoologie et de Botanique Africaines}, volume = {84 (pts 1-2)}, year = {1971}, month = {09/1971}, pages = {99-110}, chapter = {99}, author = {Taverne, L.} } @article {510, title = {Contribution a l{\textquoteright}{\'e}tude de la faune ichthyologique du bassin du fleuve S{\'e}n{\'e}gal. III. Mormyridae}, journal = {Bulletin de l{\textquoteright}Institut Fran{\c c}ais d{\textquoteright}Afrique Noire}, volume = {35}, year = {1973}, pages = {665-704}, chapter = {665}, author = {Reizer, C. and Mattei, X. and Chevalier, J.L.} }