@article {664, title = {Biogeographic barriers are differentially permeable based on traits: Movement of hypoxia tolerant mormyrid fish in the Lake Victoria basin}, year = {2024}, month = {Nov-01-2024}, pages = {102485}, abstract = {

Lake Nabugabo is a small satellite lake separated from Lake Victoria by hypoxic swamps that impose a biogeographic barrier to fish assemblages. Some species occur exclusively in Nabugabo while others show high differentiation across this barrier, yet air-breathing fishes show nearly zero genetic differentiation between the two lakes. We hypothesize that hypoxia-tolerant fishes, unlike other non-air-breathing species, would have similarly low genetic differentiation across the barrier. We used pooled RAD-seq to examine the degree of genetic differentiation in two species of non-air-breathing but hypoxia-tolerant mormyrid fishes, Marcusenius victoriae and Petrocephalus degeni. Other non-air-breathing fishes have been shown to have FST values as low as 0.05 but mostly between 0.10 and 0.20; however, we discovered that the genetic differentiation in our focal species was very low, with FST values between 0.02 and 0.04, making them much more comparable to air-breathing fishes with FST values of near zero. We conclude that this and other analogous barriers should be understood as differentially permeable depending on the traits of the organisms crossing them, such as hypoxia tolerance in this case.

}, keywords = {Differentially permeable barriers, Hypoxia tolerance, Lake Nabugabo, Lake Victoria, Mormyridae, Population connectivity}, issn = {0380-1330}, doi = {10.1016/j.jglr.2024.102485}, url = {http://dx.doi.org/10.1016/j.jglr.2024.102485}, author = {Hunt, David A.G.A. and Thomas, Quinn and Clarke, Shelby B. and Chapman, Lauren J.} } @article {644, title = {Trophic ecology of the African riverine elephant fishes (Mormyridae)}, volume = {14}, year = {2024}, month = {Aug-01-2024}, abstract = {

Multiple species of the elephant fishes (Mormyridae) commonly coexist in sympatry in most African tropical rivers and lakes. In this study, we investigated the trophic ecology and potential trophic niche partitioning of eleven mormyrid fish species from the Sanaga River system in Cameroon using the stable isotope composition of carbon and nitrogen in the muscle samples. Albeit most mormyrids mainly feed on invertebrates, we found differences in isotope ratios, and we report signs of the trophic niche partitioning among species. We further found significant differences in isotopic signatures within the Mormyrus genus, suggesting ecological niche diversification among three closely related species. We have also evaluated differences in the isotopic signals between seasons in four species, which could be possibly caused by species migration and/or anthropogenic agricultural activities. To evaluate body shape, we applied geometric morphometric analyses, and we show that most of the species are clearly morphologically separated. We focused on the mormyrid ecomorphology to identify a possible interaction between shape and ecology, and we found a relationship between the \δ13C (but not \δ15N) isotopic signal and morphology, suggesting their interplay during mormyrid evolution. Overall, we present robust evidence of the trophic niche partitioning within the mormyrid species community, and we integrate trophic ecology with morphometrics, shedding light on the enigmatic evolutionary history of these fascinating African fishes.

}, keywords = {mormyrids, stable isotopes, trophic ecology, trophic position, trophic resource portioning}, issn = {2045-7758, 2045-7758}, doi = {10.1002/ece3.70173}, url = {http://dx.doi.org/10.1002/ece3.70173}, author = {Sommer, Gina Maria and Njom, Samuel Didier and Indermaur, Adrian and Nyom, Arnold Roger Bitja and Jandov{\'a}, Kate{\v r}ina and Kukla, Jaroslav and Petrt{\'y}l, Miloslav and Hork{\'a}, Petra and Musilova, Zuzana} } @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 {603, title = {A morphological description of the sagittal otoliths of two mormyrids, Marcusenius macrolepidotus and Petrocephalus catostoma (Family: Mormyridae)}, year = {2000}, abstract = {

The morphology of the sagittal otoliths of two South African mormyrid fish, Marcusenius macrolepidotus and Petrocephalus catostoma, were studied to determine possible morphological significance. The sagittae of M. macrolepidotus and P. catostoma are kidney-shaped and oblong, respectively. The ventral margin is slightly indented in the former and slightly flattened in the latter. The sulcus acusticus of both species is archaesulcoid but mesial in M. macrolepidotus and ostio-caudal in P. catostoma. The crista inferior in M. macrolepidotus is ridge-like and well defined posteriorly and anteriorly, whereas in P. catostoma it is clearly defined posteriorly and disappears anteriorly. The otoliths of both species do not have a rostrum, antirostrum or an excisura. The differences in sagittal morphology between the two mormyrid species are distinct.

}, doi = {10.1080/15627020.2000.11407191}, url = {https://www.tandfonline.com/doi/full/10.1080/15627020.2000.11407191}, author = {Nicolaai, N.N. and Jooste, A.} } @article {599, title = {The fishes and fisheries of the Ruaha River basin, Tanzania (systematics, ecology, zoogeography, fisheries)}, year = {1967}, pages = {19 pp.}, institution = {East African Freshwater Fisheries Research Organization}, address = {Jinja, Uganda}, author = {Matthes, H.} } @article {572, title = {Sensory Specializations of Mormyrid Fish Are Associated with Species Differences in Electric Signal Localization Behavior}, journal = {Brain, Behavior and Evolution}, year = {2019}, month = {Jan-03-2019}, pages = {1 - 17}, abstract = {

The ability to localize communication signals plays a fundamental role in social interactions. For signal localization to take place, the sensory system of the receiver must extract information about distance and direction to the sender from physical characteristics of the signal. In many sensory systems, information from multiple peripheral receptors must be integrated by central sensory pathways to determine the sender location. Here, we asked whether evolutionary divergence in the electrosensory and visual systems of mormyrid fish is associated with signal localization behavior. In mormyrids, differences in the distribution of electroreceptors on the surface of the skin are associated with differences in the midbrain exterolateral nucleus (EL). Species with electroreceptors clustered in three rosettes on both sides of the head have a small and undifferentiated EL. In contrast, EL is enlarged and subdivided into anterior (ELa) and posterior (ELp) regions in species that have electroreceptors broadly \­distributed throughout the body. Interestingly, species with EL and clustered electroreceptors also have larger visual systems and higher visual acuity than species with ELa/ELp and broadly distributed electroreceptors. Species with broadly distributed electroreceptors and ELa/ELp approached a simulated conspecific by following the curved electric field lines generated by the electrosensory stimulus. In contrast, a species with small EL and clustered electroreceptors, but an enlarged visual system, followed shorter and straighter paths to the stimulus source. In the central electrosensory system, evoked field potentials in response to stimuli delivered from the left versus the right differed more in EL than in ELa/ELp. Our results suggest that signal localization behavior is associated with differences in sensory specializations. We propose that the distribution of electroreceptors on the body affects the ability of individuals to align parallel to electric field lines and maintain such alignment while approaching the signal source. The spatial resolution of sensory information relayed from the periphery to the midbrain in species with clustered electroreceptors may allow for gross, but not fine, processing of sender location. Furthermore, visual information may play an important role in localizing signaling individuals in species with small EL and clustered electroreceptors. In line with previous studies, we suggest that the physiological and behavioral differences associated with signal localization reflect adaptations to different habitats and social environments.

}, issn = {0006-8977}, doi = {10.1159/000496493}, url = {https://www.karger.com/Article/FullText/496493https://www.karger.com/Article/Pdf/496493https://www.karger.com/Article/Pdf/496493}, author = {V{\'e}lez, Alejandro and Ryoo, Da~Yeon and Bruce A Carlson} } @article {569, title = {On the Cranial Osteology of the Fishes of the Families Mormyridae, Notopteridae and Hyodontidae.}, journal = {Journal of the Linnean Society of London, Zoology}, volume = {29}, year = {1904}, month = {Jan-11-1904}, pages = {188 - 217}, doi = {10.1111/j.1096-3642.1904.tb00435.x}, url = {https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1096-3642.1904.tb00435.x}, author = {Ridewood, W. G.} } @article {534, title = {Detection of transient synchrony across oscillating receptors by the central electrosensory system of mormyrid fish}, journal = {eLife}, volume = {5}, year = {2016}, month = {Sep-06-2017}, abstract = {

Recently, we reported evidence for a novel mechanism of peripheral sensory coding based on oscillatory synchrony. Spontaneously oscillating electroreceptors in weakly electric fish (Mormyridae) respond to electrosensory stimuli with a phase reset that results in transient synchrony across the receptor population (Baker et al., 2015). Here, we asked whether the central electrosensory system actually detects the occurrence of synchronous oscillations among receptors. We found that electrosensory stimulation elicited evoked potentials in the midbrain exterolateral nucleus at a short latency following receptor synchronization. Frequency tuning in the midbrain resembled peripheral frequency tuning, which matches the intrinsic oscillation frequencies of the receptors. These frequencies are lower than those in individual conspecific signals, and instead match those found in collective signals produced by groups of conspecifics. Our results provide further support for a novel mechanism for sensory coding based on the detection of oscillatory synchrony among peripheral receptors.

}, doi = {10.7554/eLife.16851}, url = {http://elifesciences.org/lookup/doi/10.7554/eLife.16851}, author = {V{\'e}lez, Alejandro and Bruce A Carlson} } @article {485, title = {Differences in electrosensory anatomy and social behavior in an area of sympatry between two species of mormyrid electric fishes}, journal = {Journal of Experimental Biology}, volume = {219}, year = {2016}, month = {Apr-11-2016}, pages = {31 - 43}, abstract = {

Sensory systems play a key role in social behavior by mediating the detection and analysis of communication signals. In mormyrid fishes, electric signals are processed within a dedicated sensory pathway, providing a unique opportunity to relate sensory biology to social behavior. Evolutionary changes within this pathway led to new perceptual abilities that have been linked to increased rates of signal evolution and species diversification in a lineage called \‘clade A\’. Previous field observations suggest that clade-A species tend to be solitary and territorial, whereas non-clade-A species tend to be clustered in high densities suggestive of schooling or shoaling. To explore behavioral differences between species in these lineages in greater detail, I studied population densities, social interactions, and electric signaling in two mormyrid species, Gnathonemus victoriae (clade A) and Petrocephalus degeni (non-clade A), from Lwamunda Swamp, Uganda. Petrocephalus degeni was found at higher population densities, but intraspecific diversity in electric signal waveform was greater in G. victoriae. In the laboratory, G. victoriae exhibited strong shelter-seeking behavior and competition for shelter, whereas P. degeni were more likely to abandon shelter in the presence of conspecifics as well as electric mimics of signaling conspecifics. In other words, P. degeni exhibited social affiliation whereas G. victoriae exhibited social competition. Further, P. degeni showed correlated electric signaling behavior whereas G. victoriae showed anti-correlated signaling behavior. These findings extend previous reports of social spacing, territoriality, and habitat preference among mormyrid species, suggesting that evolutionary divergence in electrosensory processing relates to differences in social behavior.

}, issn = {0022-0949}, doi = {10.1242/jeb.127720}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.127720}, author = {Bruce A Carlson} } @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.} }