@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 {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} } @book {902, title = {The fishes of the Nile}, series = {Zoology of Egypt}, year = {1907}, publisher = {Pub. for the Egyptian government by H. Rees, ltd.}, organization = {Pub. for the Egyptian government by H. Rees, ltd.}, address = {London}, doi = {10.5962/bhl.title.51710}, url = {http://www.biodiversitylibrary.org/item/110263$\#$page/1/mode/1up}, author = {George A. Boulenger} } @article {1822, title = {A critical revision of the churchill snoutfish, genus Petrocephalus Marcusen, 1854 (Actinopterygii: Teleostei: Mormyridae), from southern and eastern Africa, with the recognition of Petrocephalus tanensis, and the description of five new species}, journal = {Journal of Natural History}, volume = {46}, year = {2012}, month = {09/2012}, pages = {2179{\textendash}2258}, abstract = {

We morphologically and genetically studied the southern African electric fish Petrocephalus catostoma, or churchill, and its six nominal species, five of which by synonymization (three valid subspecies). We reinstate the synonymized species, and recognize Petrocephalus tanensis (Whitehead and Greenwood, 1959) from the Tana River in Kenya, also using electric organ discharges. The Okavango delta (Botswana) is inhabited by Petrocephalus okavangensis sp. nov. and Petrocephalus magnitrunci sp. nov., and the Namibian Cunene River by Petrocephalus magnoculis sp. nov. We recognize Petrocephalus petersi sp. nov. for the Lower Zambezi River (Mozambique), and Petrocephalus longicapitis sp. nov. for the Upper Zambezi River (Namibia). The Lufubu River in Northern Zambia is inhabited by Petrocephalus longianalis sp. nov. For the southern churchill, Petrocephalus wesselsi Kramer and Van der Bank, 2000, we confirm intraspecific and interspecific differentia- tion. Sequence data from mitochondrial DNA confirm differentiation of two new western and two eastern species, forming mutual sister groups.

}, keywords = {allopatric speciation, electric organ discharges, molecular genetics, morphometrics, Systematics}, issn = {ISSN 0022-2933}, doi = {10.1080/00222933.2012.708452}, url = {http://dx.doi.org/10.1080/00222933.2012.708452}, author = {Bernd Kramer and Roger Bills and P. Skelton and Michael Wink} }