@article {671, title = {Phylogenetic reconstruction of African weakly electric fish (Campylomormyrus spp.) is suggestive of ancient introgression events}, journal = {Molecular Phylogenetics and Evolution}, volume = {214}, year = {2026}, month = {Jan-01-2026}, pages = {108452}, abstract = {

The African weakly electric fish genus Campylomormyrus belongs to the species-rich family Mormyridae and comprises 15 described species. Previous species trees that focus on the genus, have included at most ten species. The resulting phylogenies have been used to explain the evolution of the species-specific electrical organ discharge (EOD) and interpreted in the context of sympatric speciation caused by disruptive selection. However, available molecular phylogenies that are focused on the Campylomormyrus genus rely only on a limited number of genetic markers. Here, we used ddRAD sequencing to genotype 65 individuals from twelve Campylomormyrus species and Gnathonemus petersii at more than 8,000 SNPs. We reconstruct a robust species tree that is suggestive of ancient introgression events between different species, which might affect both genetic and trait variability in the genus. Different levels of genetic and EOD diversity in two significant Campylomormyrus clades reveals that i) certain species might be in early stages of their speciation process, ii) that hybridization/introgression occurs in mormyrids and iii) that EOD-related genes could be potential speciation genes. Our genomic approach demonstrates the significance of these findings in understanding the evolution of Campylomormyrus.

}, keywords = {Ancient introgression, Campylomormyrus, ddRAD sequencing, EOD, phylogeny, speciation}, issn = {1055-7903}, doi = {10.1016/j.ympev.2025.108452}, url = {https://doi.org/10.1016/j.ympev.2025.108452}, author = {Canitz, Julia and Kirschbaum, Frank and Vendrami, David L.J. and Mamonekene, Victor and Tiedemann, Ralph} } @article {496, title = {Marcusenius desertus sp. nov. (Teleostei: Mormyridae), a mormyrid fish from the Namib desert}, journal = {African Journal of Aquatic Science}, year = {2016}, month = {Jul-03-2016}, pages = {1 - 18}, abstract = {

We critically compared Marcusenius specimens from the mouth of the Cunene River on the Namibia/Angola border, a harsh desert environment on the Atlantic Ocean coast virtually devoid of aerial insects with aquatic larvae which are an important food item, with Marcusenius multisquamatus Kramer \& Wink, 2013 from the escarpment region of that same river, in a relatively rich and productive subtropical savannah environment. River mouth specimens were differentiated in morphology and electric organ discharges, as determined by ANOVA/MANOVA comparisons, principal component and discriminant analyses on morphological and electrophysiological characters, and genetics, including sequences of the mitochondrial cytochrome b gene, indicating reproductive isolation. Specimens from the river mouth differed from M. multisquamatus, their closest relatives, by having a shorter snout, a smaller eye diameter, and smaller nares separation. River mouth specimens were also differentiated from other, increasingly less-close relatives, such as M. altisambesi Kramer et al., 2007 from the Okavango River, Botswana, and from M. krameri Maake et al., 2014 from the Limpopo System, South Africa. We therefore designate the new species Marcusenius desertus sp. nov. for the Cunene River mouth population.

}, keywords = {ecology, electric organ discharges, genetic differentiation, morphology, phylogeography, speciation}, issn = {1608-5914}, doi = {10.2989/16085914.2015.1137855}, url = {http://www.tandfonline.com/doi/full/10.2989/16085914.2015.1137855}, author = {Bernd Kramer and F. Herman van der Bank and Michael Wink} } @article {412, title = {The electric organ discharges of the Petrocephalus species (Teleostei: Mormyridae) of the Upper Volta System}, journal = {Journal of Fish Biology}, volume = {74}, number = {1}, year = {2009}, note = {395IDTimes Cited:0Cited References Count:40}, month = {Jan}, pages = {54-76}, abstract = {

In this study, a first comparative investigation of all four species of Petrocephalus (P. bovei, P. bane, P. soudanensis and P. cf. pallidomaculatus) present in the Upper Volta system and their electric organ discharges (EOD) was conducted. It was found that P. bovei was the most widespread (in terms of habitat use), but in several places P. bovei, P. soudanensis and P. cf. pallidomaculatus occurred syntopically. All species emitted a triphasic signal, and with very few exceptions, the Petrocephalus species of the Upper Volta system could clearly be identified on the basis of their EOD waveforms. The most obvious differences between species in EOD waveforms were in amplitude of the last phase, total duration and fast Fourier transformation (FFT) peak frequency. No sexual dimorphism was present in the EOD of any species although external dimorphism, i.e. an indentation at the base of the anal fin of mature males, was common. The EOD waveform diversity in the Upper Volta principally resembled that found in four sympatric Petrocephalus species from the OgoouE system (Gabon) and might play a role in species recognition and speciation processes.

}, keywords = {active electrolocation, central-africa, communication, eod waveform, fishes mormyridae, gnathonemus-petersii mormyridae, osteoglossomorpha, pendjari, pollimyrus-isidori, recognition, sex-differences, speciation, variability, water conductivity, weakly electric fish, west africa}, isbn = {0022-1112}, url = {://000262516900004}, author = {Moritz, T. and Engelmann, J. and Linsenmair, K. E. and G. von der Emde} } @article {410, title = {Differentiation of morphology, genetics and electric signals in a region of sympatry between sister species of African electric fish (Mormyridae)}, journal = {Journal of Evolutionary Biology}, volume = {21}, number = {4}, year = {2008}, note = {312QYTimes Cited:5Cited References Count:70}, month = {Jul}, pages = {1030-1045}, abstract = {

Mormyrid fishes produce and sense weak electric organ discharges (EODs) for object detection and communication, and they have been increasingly recognized as useful model organisms for studying signal evolution and speciation. EOD waveform variation can provide important clues to sympatric species boundaries between otherwise similar or morphologically cryptic forms. Endemic to the watersheds of Gabon (Central Africa), Ivindomyrus marchei and Ivindomyrus opdenboschi are morphologically similar to one another. Using morphometric, electrophysiological and molecular characters [cytochrome b sequences and amplified fragment length polymorphism (AFLP) genotypes], we investigated to what extent these nominal mormyrid species have diverged into biological species. Our sampling covered the known distribution of each species with a focus on the Ivindo River, where the two taxa co-occur. An overall pattern of congruence among datasets suggests that I. opdenboschi and I. marchei are mostly distinct. Electric signal analysis showed that EODs of I. opdenboschi tend to have a smaller initial head-positive peak than those of I. marchei, and they often possess a small third waveform peak that is typically absent in EODs of I. marchei. Analysis of sympatric I. opdenboschi and I. marchei populations revealed slight, but significant, genetic partitioning between populations based on AFLP data (F-ST approximate to 0.04). Taken separately, however, none of the characters we evaluated allowed us to discriminate two completely distinct or monophyletic groups. Lack of robust separation on the basis of any single character set may be a consequence of incomplete lineage sorting due to recent ancestry and/or introgressive hybridization. Incongruence between genetic datasets in one individual, which exhibited a mitochondrial haplotype characteristic of I. marchei but nevertheless fell within a genetic cluster of I. opdenboschi based on AFLP genotypes, suggests that a low level of recent hybridization may also be contributing to patterns of character variation in sympatry. Nevertheless, despite less than perfect separability based on any one dataset and inconclusive evidence for complete reproductive isolation between them in the Ivindo River, we find sufficient evidence to support the existence of two distinctive species, I. opdenboschi and I. marchei, even if not \’biological species\’ in the Mayrian sense.

}, keywords = {adaptive radiation, aflp, electric fish, electric organ discharge, gnathonemus-petersii mormyridae, introgression, markers, mitochondrial-DNA, mormyroidea, phylogeny, population-structure, reproductive isolation, speciation, teleostei}, isbn = {1010-061X}, url = {://000256687100010}, author = {S{\'e}bastien Lavou{\'e} and John P Sullivan and Matthew E Arnegard and Carl D Hopkins} }