02147nas a2200265 4500008004100000022001400041245013300055210006900188260001600257300001100273490000800284520132700292653002601619653002001645653002101665653000801686653001401694653001501708100001801723700002201741700002601763700002301789700002101812856004801833 2026 eng d a1055-790300aPhylogenetic reconstruction of African weakly electric fish (Campylomormyrus spp.) is suggestive of ancient introgression events0 aPhylogenetic reconstruction of African weakly electric fish Camp cJan-01-2026 a1084520 v2143 a

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.

10aAncient introgression10aCampylomormyrus10addRAD sequencing10aEOD10aphylogeny10aspeciation1 aCanitz, Julia1 aKirschbaum, Frank1 aVendrami, David, L.J.1 aMamonekene, Victor1 aTiedemann, Ralph uhttps://doi.org/10.1016/j.ympev.2025.10845201771nas a2200217 4500008004100000022001400041245006900055210006500124260001600189300001000205490000800215520117700223653001701400653001601417653000801433653001701441100001701458700001701475700002001492856004101512 1976 eng d a0302-982400aThe electric organ of a mormyrid as a current and voltage source0 aelectric organ of a mormyrid as a current and voltage source cJan-01-1976 a65-880 v1103 a

We have examined how the electric organ discharge (EOD) of a mormyrid (Gnathonemus petersii) is affected by changes in resistive load (Figs. 3, 4, 5). We have also shown how this load depends on resistivity and distance to non-conducting boundaries (Figs. 10, 11). When resistive load was varied, voltage and current were related in a linear, battery-like manner for the initial, head positive phase of the EOD (Figs. 4, 5). This linear relation made it possible to estimate first phase e.m.f, and source resistance. For the second, head negative phase, however, voltage rose to a peak and then fell as resistance increased. Furthermore, the waveform of the second but not the first phase was strongly affected by load changes. These second phase features were shown to reflect a dependence of second phase e.m.f, on first phase current. A linear and battery-like relation between second phase voltage and current was seen when first phase load was held constant while varying second phase load (Fig. 6). These results on the behavior of the whole electric organ can be understood in terms of the underlying properties of the cellular generators, the electrocytes

10aconductivity10aelectrocyte10aEOD10aeod waveform1 aBell, C., C.1 aBradbury, J.1 aRussell, C., J. uhttp://dx.doi.org/10.1007/bf0065678203856nas a2200277 4500008004100000022001400041245013400055210006900189260001600258300001400274490000800288520299800296653003003294653000803324653002903332653000803361653002503369653001503394653001403409653001103423653002503434100002203459700002403481700002103505856005203526 2016 eng d a1313-298900aCryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa0 aiCryptomyrusi a new genus of Mormyridae Teleostei Osteoglossomor cAug-02-2016 a117 - 1500 v5613 a

Abstract
We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In C. ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.

Résumé
Nous avons démontré avec des marqueurs mitochondriaux et nucléaires que trois spécimens de poissons mormyridés faiblement électriques, collectés à trois localités au Gabon sur une période de 13 ans, forment une lignée inconnue au sein de la sous famille des Mormyrinae dont nous avons déterminé la position phylogénétique. Nous décrivons un nouveau genre et deux nouvelles espèces pour ces trois spécimens. Cryptomyrus, nouveau genre, se distingue des autres genres de mormyridés par une combinaison de caractères de l’écaillure, morphométriques, et dentaires. Cryptomyrus ogoouensis, nouvelle espèce, se distingue de sa seule espèce congénérique par sa nageoire anale qui commence nettement en avant de sa nageoire dorsale, son pédoncule caudal gracile et les lobes de sa nageoire caudale pratiquement aussi longs que son pédoncule caudal. Chez Cryptomyrus ona, nouvelle espèce, la nageoire anale commence légèrement en avant de l’origine de la nageoire dorsale, le pédoncule caudal est large, et les lobes de la nageoire caudale sont plus courts que le pédoncule caudal. La découverte ininterrompue de nouveaux taxa dans le «clade de basse Guinée» des Mormyridae illustre notre connaissance incomplète de la diversité des poissons de l’ouest de l’Afrique centrale. Nous présentons une clé révisée des genres de Mormyridae de basse Guinée.

10aAfrican freshwater fishes10aDNA10aelectric organ discharge10aEOD10aintegrative taxonomy10aMormyrinae10aphylogeny10ararity10aweakly electric fish1 aSullivan, John, P1 aLavoué, Sébastien1 aHopkins, Carl, D uhttp://zookeys.pensoft.net/articles.php?id=7137