@article {615, title = {Marcusenius elegans: a replacement name for Marcusenius gracilis Kramer 2013 (Osteoglossiformes: Mormyridae), a secondary junior homonym of Marcusenius senegalensis gracilis (Pellegrin 1922)}, volume = {5175}, year = {2022}, month = {Aug-18-2022}, pages = {499-500}, abstract = {

The West African mormyrid Marcusenius gracilis Kramer 2013 is a secondary homonym of Gnathonemus gracilis Pellegrin 1922 when both species are placed in the same genus Marcusenius (International Code of Zoological Nomenclature, article 57.3). Marcusenius gracilis was first described by Kramer (2013: 123), based on a holotype and 16 paratypes from Ivory Coast, West Africa. The taxon was subsequently treated as a valid species of Marcusenius by Kramer \& Wink (2013: 2334), and by Fricke et al. (2022). Kramer (2013) was not aware of Gnathonemus gracilis Pellegrin 1922, which was originally described by Pellegrin (1922: 221), based on a specimen from the Gribingui River, Lake Chad basin, in today\’s Central African Republic. The holotype is extant (MNHN 1922-0023). The taxon was treated as a synonym of the West African species Marcusenius senegalensis (Steindachner 1870), but as a valid subspecies (Gosse 1984: 89, L\év\êque et al. 1991: 138). Marcusenius senegalensis gracilis (Pellegrin 1922) has precedence over Marcusenius gracilis Kramer 2013, and the latter must be renamed when both taxa are classified in genus Marcusenius. Marcusenius elegans nom. nov. is herein proposed as the replacement name for Marcusenius gracilis Kramer 2013. The new species epithet is based on the Latin word elegans, meaning elegant, referring to its slender body; the name is treated as an adjective.

}, issn = {1175-5334, 1175-5326}, doi = {10.11646/zootaxa.5175.4.8}, url = {http://dx.doi.org/10.11646/zootaxa.5175.4.8}, author = {Fricke, R. and Bernd Kramer} } @inbook {605, title = {Communication and Waveform Analysis in Weakly Electric Fishes With Special Emphasis on Mormyrids}, booktitle = {The Senses: A Comprehensive Reference}, year = {2020}, pages = {255-280}, publisher = {Elsevier}, organization = {Elsevier}, edition = {2nd}, abstract = {

The electric sense in fishes was discovered in the 1950s. African snoutfish (Mormyridae) and South American knifefishes (Gymnotiformes) generate electric fields for testing their environment by Active Electrolocation, and for communication. These fishes\’ electric organ discharges (EODs) are species-specific (or \–characteristic) pulses or continuous waves, and vary widely in waveform, duration (frequency) and strength. In mormyrids the sequence (or pattern) of pulse intervals carries motivational and species-specific information. In a natural hybrid species complex, choosy females of the parent species block a speciation reversal by their preference for conspecific EOD waveforms, and rejection of the hybrid form. Electrosensory discrimination thresholds appear adapted to the fine detail of the EOD pulse waveforms on a ms-scale, with spectral cues not required in Pollimyrus adspersus. In some mormyrid species, breeding males add a strong D.C. component to their EOD, which attracts females but also\ low-frequency sensitive catfish predators. In several species, specific EOD patterns, as well as loud vocalizing, accompany courtship and spawning. The larvaes\’ early EODs of long pulse duration and initially low rate is replaced by an adult short EOD in young juveniles; parental care is present in Pollimyrus species. Three syntopic species gave examples of conflictual and cooperative electrocommunication in a semi-natural environment. Eigenmannia, a wave gymnotiform fish, is highly phase sensitive to stimuli of 0 Hz frequency difference, which evoke a Jamming Avoidance Response (which is a frequency shift away from the stimulus). The strength of the JAR depends on the phase difference stimulus to EOD. At a sufficient frequency difference, trained, food-rewarded Eigenmannia discriminate waveforms by a temporal mechanism that does not require spectral cues. Eigenmannia is incapable of discriminating stimuli that are phase-locked at maintained frequency identity.

}, isbn = {9780128054093}, doi = {10.1016/b978-0-12-805408-6.00027-0}, url = {https://epub.uni-regensburg.de/43937/1/Kramer\%2C\%20The\%20Senses\%202020_corrected.pdf}, author = {Bernd Kramer} } @article {582, title = {Female choice by electric pulse duration: attractiveness of the males{\textquoteright} communication signal assessed by female bulldog fish, Marcusenius pongolensis (Mormyridae, Teleostei)}, journal = {Journal of Experimental Biology}, volume = {211}, year = {2008}, month = {Mar-06-2009}, pages = {1969 - 1977}, abstract = {

In adult males of the South African weakly electric bulldog fish, Marcusenius pongolensis, the duration of the electric organ discharge (EOD) increases with body size over lifetime. Although there is experimental support for intrasexual selection (male\–male competition) having shaped the males\&$\#$39; EOD pulse duration in evolution, nothing is known about intersexual selection, such as female choice. Playback of 25 natural male EODs of pulse duration varying from 320 \μs (close to the average female value) to 716\μ s, to eight female experimental subjects elicited approach, head butts and circling behaviour. The rate of head butts on the dipole electrode model increased significantly with stimulus pulse duration in seven out of eight experimental subjects. In ten experimental female subjects we contrasted the shortest playback pulse with simultaneous playback of one of four longer ones (424, 524, 628 and 716 \μs). Pooled responses for all experimental subjects were stronger for the dipole playing back the longer pulse in a pulse pair. The difference in the number of head butts (\Δhead butts) that were dealt the two dipoles per 60 s test session increased significantly with the difference in pulse duration (\Δpulse duration). The increase followed a significant linear trend (P\<0.0001). Similar results were obtained for \Δassociation time, \Δcircles with head butts, and\Δ circles without head butts. These results suggest that a male\&$\#$39;s reproductive success is enhanced by longer, i.e. more attractive EODs, and that both intra- and intersexual selection must have played a significant role in shaping the EOD of male M. pongolensis.

}, issn = {0022-0949}, doi = {10.1242/jeb.016949}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.016949https://syndication.highwire.org/content/doi/10.1242/jeb.016949}, author = {Machnik, P. and Bernd Kramer} } @article {581, title = {Electrosensory prey detection in the African sharptooth catfish, Clarias gariepinus (Clariidae), of a weakly electric mormyrid fish, the bulldog (Marcusenius macrolepidotus )}, year = {2000}, abstract = {

During their seasonal runs in the Okavango and other freshwater bodies in southern Africa, the sharptooth catfish, Clarias gariepinus, specialises on the bulldog, Marcusenius macrolepidotus, as its main prey. We examined whether the catfish can locate bulldogs by detecting their pulse-type electric organ discharges (EODs). The electrosensory threshold for single-cycle, monopolar square-wave pulses was exceedingly low (down to 13 \µVp\–p/cm for 4-ms pulses) in trained, food-rewarded sharptooth catfish (n=4), confirming the results of Lissmann and Machin who were, however, unable to identify a biological function. Other stimulus pulse waveforms (single-cycle, monopolar as well as bipolar sine-wave pulses) were also effective stimuli according to their spectral low-frequency energy contents (0\– 30 Hz). Male bulldogs display an EOD pulse approximately 10\× the duration of female EODs (\≈0.5 ms). The C. gariepinus threshold for field-recorded playbacks of a male bulldog EOD (of long duration) was 103 \µVp\–p/cm, whereas the brief female and juvenile EODs were not detected (using intensities of natural EODs). EODs of other mormyrids were detected when either monopolar or of long duration. Signal source amplitude increased linearly with standard length (SL) in bulldogs. Signal reach, as calculated from signal source amplitude and receiver sensitivity, is up to 150 cm for a large male bulldog (SL 27.5 cm), and 83 cm for a male that has just turned sexually mature (SL 12.6 cm). Therefore, most bulldogs eaten by catfish are probably male, in agreement with the size distribution of bulldogs found in catfish stomachs. These results suggest that sharptooth catfish rely heavily on their acute electrical sense during hunting, and an important function for electroreception in an African catfish has been identified.

}, doi = {10.1007/s002650000232}, url = {http://link.springer.com/10.1007/s002650000232}, author = {Hanika, S. and Bernd Kramer} } @article {570, title = {Phylogenetic relationships between eight African species of mormyriform fish (Teleostei, Osteichthyes): resolution of a cryptic species, and reinstatement of Cyphomyrus Myers, 1960}, journal = {Biochemical Systematics and Ecology}, volume = {24}, year = {1996}, pages = {275-290}, chapter = {275}, abstract = {

Phylogenetic relationships between seven elephantfish species from five genera (Mormyridae) that are endemic to southem Africa, and the Nile knifefish of the sister family, Gymnamhidae, were determined using biochemical genetic data, behaviour (the waveforms of the electric organ discharge), morphology, and habitat and food preferences. The results confirmed the existence of an undescribed species of Hippopotamyrus, and that H.ansorgii and H.discorhynchus are not congeners.These distinctions had been suggested by differences in electric organ discharge wavefonns and are here substantiated by morphological and genetic data. We recommend the reinstatement of Cyphomyrus discorhynchus (Peters, 1852). Genetic distance (D, Nei, 1972) values suggest confamilial genera (D average of 1.09 for all species studied, and 0.715 for southern African species), with the exception of the sympatric and congeneric species: H. ansorgii and H. sp. (D=0.423). Phylogenies based on morphological and electrophoretic data are congruent.

}, doi = {10.1016/0305-1978(96)00026-9}, url = {https://www.sciencedirect.com/science/article/pii/0305197896000269?via\%3Dihub}, author = {F. Herman van der Bank and Bernd Kramer} } @article {541, title = {Electric organ discharges of South African Marcusenius species (Teleostei: Mormyridae) and their effectiveness as indicators of local species diversity}, journal = {Zootaxa}, volume = {4200}, year = {2016}, month = {May-11-2018}, pages = {367}, abstract = {

Recent morphological and genetic studies have revealed two new species of snoutfish in South Africa, Marcusenius caudisquamatus and M. krameri, which had been confused with M. pongolensis, the South African bulldog fish. All known mormyriform fish are nocturnal and emit electric organ discharges (EODs) for communication that are characteristic for their species. This paper examines whether or not the EODs of these three closely-related South African species can be differentiated from each other. An EOD pulse of a bulldog fish consists of a head-positive phase P, followed by a head-negative phase N of short duration. We measured and compared six variables of the EOD pulse waveform for South African samples for the three species from different locations using MANOVA, ANOVA and Discriminant Analysis, with M. devosi from Kenya as an outgroup. The EOD waveforms, normalized to the same P-phase amplitude, varied significantly from each other in four variables, most strongly in the amplitude of the N phase and the duration of the P phase. In two species, M. devosi and M. krameri, there was no evidence of difference between sexes, in contrast to M. pongolensis and M. caudisquamatus whose male pulses were of longer duration. M. devosi and M. krameri were statistically significantly independent of each other and of any other group studied. By contrast, the M. pongolensis specimens from different locations showed a high degree of variability amongst each other, including significant separation, and overlap with M. caudisquamatus.

}, issn = {1175-5326}, doi = {10.11646/zootaxa.4200.310.11646/zootaxa.4200.3.2}, url = {http://biotaxa.org/Zootaxa/issue/view/zootaxa.4200.3}, author = {Bernd Kramer and Pholoshi A. Maake and Ofer Gon} } @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 {215, title = {Intraspecific variability of the pulse-type discharges of the African electric fishes, Pollimyrus isidori and Petrocephalus bovei (Mormyridea, Teleostei), and their dependence on water conductivity.}, journal = {Experimental Biology}, volume = {47}, year = {1988}, pages = {227-238}, author = {Bratton, B.O. and Bernd Kramer} } @article {879, title = {Evidence for parapatric speciation in the mormyrid fish, Pollimyrus castelnaui (Boulenger, 1911) from the Okavango-Upper Zambezi River systems: P. marianne sp. nov., defined by electric organ discharges, morphology and genetics}, journal = {Environmental Biology of Fishes}, volume = {67}, year = {2003}, pages = {47 - 70}, abstract = {

We report on parapatric speciation in the mormyrid fish,Pollimyrus castelnaui (Boulenger, 1911), from the Okavango and the Upper Zambezi River systems. We recognise samples from the Zambezi River as a distinct species, P. marianne, displaying an eastern phenotype of electric organ discharge (EOD) waveform (Type 3) that is distinct from the western EOD phenotype (Type 1) observed in P. castelnaui samples from the neighbouring Okavango. Samples from the geographically intermediate Kwando/Linyanti River (a tributary of the Zambezi that is also intermittently connected to the Okavango) presented a more variable third EOD phenotype (Type 2). In 13 out of 14 morphological characters studied, the Zambezi River samples differed significantly from P. castelnaui. Morphologically and in EOD characters, the Kwando/Linyanti fish are distinct from both P. castelnaui and P. marianne. Sequence analysis of the mitochondrial cytochrome b gene unambiguously reveals that specimens from the Zambezi River System form a well supported taxon which clearly differs from P. castelnaui from the Okavango (1.5\–2.5\% sequence divergence).Within specimens from theKwando\–Zambezi System some geographic differentiation can be detected (nucleotide substitutions up to 0.6\%); but groups cannot be resolved with certainty. Significant allozyme differences were found between the Okavango and all other EOD types from the Upper Zambezi System, and, within the Zambezi System, between the Kwando (Type 2) and Zambezi (Type 3) individuals. The low Wright\’s fixation index values, the lack of fixed allele differences, and small genetic distances provide little evidence for speciation between groups within the Zambezi System, but moderate to great fixation index values and significant allele frequency differences were observed between the Okavango and the other fishes. It is concluded that within the Zambezi System, differentiation between Kwando/Linyanti and Zambezi populations (as revealed by morphology and EOD waveform comparisons) is so recent that substantial genetic (allozyme and mitochondrial sequence) differences could not have evolved, or were not detected.

}, issn = {03781909}, doi = {10.1023/A:1024448918070}, author = {Bernd Kramer and F. Herman van der Bank and Flint, Nicolette and Sauer-G{\"u}rth, Hedi and Michael Wink} } @article {425, title = {The southern churchill, Petrocephalus wesselsi, a new species of mormyrid from South Africa defined by electric organ discharges, genetics, and morphology}, journal = {Environmental Biology of Fishes}, volume = {59}, year = {2000}, pages = {393-413}, author = {Bernd Kramer and F. Herman van der Bank} } @article {202, title = {Allopatric differentiation in the Marcusenius macrolepidotus species complex in southern and eastern Africa: the resurrection of M. pongolensis and M. angolensis, and the description of two new species (Mormyridae, Teleostei)}, journal = {Journal of Natural History}, volume = {41}, number = {9-12}, year = {2007}, pages = {647-708}, doi = {10.1080/00222930701250987}, author = {Bernd Kramer and P. Skelton and F. Herman van der Bank and Michael Wink} } @article {350, title = {Allopatric differentiation in the acoustic communication of a weakly electric fish from southern Africa, Marcusenius macrolepidotus (Mormyridae, Teleostei)}, journal = {Behavioral Ecology and Sociobiology}, volume = {61}, year = {2006}, month = {12/2006}, pages = {385 - 399}, abstract = {

A few species of the weakly electric snoutfish, the African freshwater family Mormyridae, have been reported to vocalise. However, allopatric populations of a single species were never compared. Members of three allopatric Marcusenius macrolepidotus populations, originating from the Upper Zambezi River in Namibia, the Buzi River (Mozambique), and the Incomati River system in South Africa, vocalised with pulsatile growl- and tonal hoot sounds in dyadic confrontation experiments. A high rate of growling accompanied territorial and agonistic interactions and also non-threatening interactions between males and females, which in one pair appeared to be courtship. Growl sound characteristics of M. macrolepidotus from the Incomati system differed from those of the Upper Zambezi in a significantly higher frequency of the first harmonic (mean, 355 Hz vs 266 Hz). The two vocalising males from the Buzi River generated growls about twice as long as the other fish. Furthermore, the growl pulse period was about 4 ms in M. macrolepidotus from the Upper Zambezi River and from the Incomati system, but 6 ms in M. macro- lepidotus from the Buzi River. Hoots were only observed in agonistic encounters. Hoot oscillograms showed a sinusoi- dal waveform, and the mean duration of this sound was similar in Incomati system fish (mean, 161 ms), Upper Zambezi fish (172 ms) and Buzi fish (103 and 145 ms for\ the two vocalising individuals). The mean frequency of the first hoot harmonic was higher in Incomati system fish (326 Hz) than in Upper Zambezi fish (245 Hz). Both growl and hoot occurred only in the presence of conspecifics, probably signalling the presence and condition of an opponent, territory owner or potential mate. This is the first evidence for (1) sound production and acoustical commu- nication in another species and genus, M. macrolepidotus, from southern Africa to be (2) geographically differentiated.

}, issn = {1432-0762}, doi = {10.1007/s00265-006-0267-0}, author = {Lamml, Michael and Bernd Kramer} } @article {352, title = {Electric signalling and reproductive behaviour in a mormyrid fish, the bulldog Marcusenius macrolepidotus (South African form)}, journal = {Journal of Ethology}, volume = {23}, year = {2005}, month = {7/2005}, pages = {113 - 125}, issn = {1439-5444}, doi = {10.1007/s10164-004-0136-0}, author = {Werneyer, Martin and Bernd Kramer} } @article {402, title = {Hippopotamyrus ansorgii species complex in the Upper Zambezi River System with a description of a new species, H. szaboi (Mormyridae)}, journal = {Zoologica Scripta}, volume = {33}, year = {2004}, month = {01/2004}, pages = {1 - 18}, issn = {1463-6409}, doi = {10.1111/j.1463-6409.2004.00132.x}, author = {Bernd Kramer and F. Herman van der Bank and Michael Wink} } @article {351, title = {Electrosensory basis for individual recognition in a weakly electric, mormyrid fish, Pollimyrus adspersus (G{\"u}nther, 1866)}, journal = {Behavioral Ecology and Sociobiology}, volume = {55}, year = {2003}, month = {12/2003}, pages = {197 - 208}, issn = {1432-0762}, doi = {10.1007/s00265-003-0690-4}, author = {Paintner, Stephan and Bernd Kramer} } @inbook {355, title = {Electric Communication and Electrolocation}, booktitle = {Encyclopedia of Neuroscience}, year = {2009}, pages = {1038 - 1045}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, isbn = {978-3-540-29678-2}, doi = {10.1007/978-3-540-29678-2_2913}, author = {Bernd Kramer}, editor = {Binder, Marc D. and Hirokawa, Nobutaka and Windhorst, Uwe} } @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} } @article {642, title = {The Victoria Falls, a species boundary for the Zambezi Parrotfish, Cyphomyrus discorhynchus (Peters, 1852), and the resurrection of Cyphomyrus cubangoensis (Pellegrin, 1936) (Mormyridae: Teleostei)}, journal = {Journal of Natural History}, volume = {45}, number = {43-44}, year = {2011}, abstract = {

Cyphomyrus discorhynchus occurs in the Zambezi River and in the linked systems of the Kwando and the Okavango. We collected specimens from both above and below the Victoria Falls and recorded Electric Organ Discharges. We found a marked degree of anatomical differentiation among the specimens from the Zambezi delta to the Victoria Falls that represents a subspecific, geographical cline, reflecting the great length (1400 km) and high ecological diversity of that river section (Lower and Middle Zambezi). We confirm that the populations above the Falls (i.e. Upper Zambezi, Kwando and Okavango) are differentiated from those below, possessing fewer dorsal fin rays (a median of 30-31 rather than 33-34). The waveforms of the electric organ discharge pulses have four phases and show geographic variation but were briefer for specimens from below the Falls. We resurrect Cyphomyrus cubangoensis (Pellegrin, 1936) for the Upper Zambezi/Kwando/Okavango system

}, author = {Bernd Kramer and F. Herman van der Bank} } @article {349, title = {A new species of Slender Stonebasher within the Hippopotamyrus ansorgii complex from the Cunene River in southern Africa (Teleostei: Mormyriformes)}, journal = {Journal of Natural History}, volume = {44}, year = {2010}, month = {9/2010}, pages = {2213 - 2242}, issn = {0022-2933}, doi = {10.1080/00222931003764089}, author = {Bernd Kramer and Ernst Swartz} } @article {852, title = {Morphological and electrophysiological field observations on electric freshwater fish of the genus Mormyrops M{\"u}ller 1843 (Teleostei: Mormyridae) from West and southern Africa}, journal = {African Journal of Aquatic Science}, volume = {38}, year = {2013}, month = {11/2013}, pages = {31 - 41}, abstract = {

Different specimens of Mormyrops anguilloides (Linnaeus 1758) were reported to display electric organ discharge (EOD) pulses of either initially head-positive or initially negative polarity, a hypothetical sex difference that has not been substantiated to date. The morphology and EODs of M. anguilloides of both sexes and a sexually mature size from the Comoé and Bandama rivers, Côte d\’Ivoire, and the Lower and Middle Zambezi, Mozambique, displayed initially positive EODs. The morphologically similar M. breviceps Steindachner 1895 of both sexes and a sexually mature size from the Bandama River displayed initially head-negative EODs of biphasic waveform and long duration (0.93\–1.15 ms) in the very-low-frequency spectral range. Mormyrops anguilloides from the Comoé and Bandama rivers were differentiated in caudal peduncle depth and in EOD waveform, pulse duration and spectral energy content. The former samples displayed a biphasic, lower-frequency EOD pulse of up to 0.42 ms duration, the latter a tetraphasic, high-frequency EOD of up to 0.33 ms. It is suggested that reports of EODs of both polarities in M. anguilloides indicate the presence of an unrecognised species.

}, issn = {1727-9364}, doi = {10.2989/16085914.2013.791244}, url = {http://dx.doi.org/10.2989/16085914.2013.791244}, author = {Bernd Kramer} } @article {876, title = {East{\textendash}west differentiation in the Marcusenius macrolepidotus species complex in Southern Africa: the description of a new species for the lower Cunene River, Namibia (Teleostei: Mormyridae)}, journal = {Journal of Natural History}, volume = {47}, year = {2013}, month = {09/2013}, pages = {2327 - 2362}, abstract = {

This paper critically compares the Southern African bulldog fish species Marcusenius macrolepidotus (Peters, 1852), inhabiting the eastern Lower Zambezi River, and Marcusenius altisambesi Kramer et al., 2007, inhabiting the central Upper Zambezi River, with bulldog fish samples from the western lower Cunene River, a 2600-km range from the Indian Ocean to the Atlantic. The three species or forms are well differentiated in morphology and molecular genetics, and dif- ferentiation is also present in electric organ discharges. Marcusenius altisambesi and the Cunene sample, which we recognize as Marcusenius multisquamatus sp. nov., are closely related and form a sister taxon to M. macrolepidotus. This result is based on the analysis of mitochondrial cytochrome b sequences and genomic Inter-simple-sequence-repeat fingerprinting. Morphological adaptations to life in a torrential escarpment river seem to be present in M. multisquamatus sp. nov. when compared with M. altisambesi, which lives in a reservoir river that periodi- cally floods the savannah.

}, issn = {1464-5262}, doi = {10.1080/00222933.2013.798699}, author = {Bernd Kramer and Michael Wink} } @article {882, title = {Differentiation in morphology and electrical signalling in four species of para- and sympatric Marcusenius (Teleostei: Mormyridae) from C{\^o}te d{\textquoteright}Ivoire, West Africa}, journal = {Marine and Freshwater Behaviour and Physiology}, volume = {46}, year = {2013}, month = {03/2013}, pages = {105 - 133}, abstract = {

Marcusenius Gill, 1862 species were sampled from the Bandama River and the Comoé River in Côte d\’Ivoire, West Africa. Marcusenius gracilis sp. nov. was differentiated from M. senegalensis (Steindachner, 1870), Marcusenius ussheri (Günther, 1867) and M. furcidens (Pellegrin, 1920) in electric organ discharges (EOD), and morphologically from all other West African congeners. Principal component analysis showed significant morphological differentiation among the four Ivorian species. Principal component 1 was loaded most strongly by characters affecting swimming power and manoeuvrability. The morphologically most similar pair, M. furcidens and M. gracilis sp. nov., are distinguished by their EOD waveforms and a sexual dimorphism in the anal fin base in the latter not present in the former. M. ussheri is distinguished by a sexual dimorphism in its EOD waveform not observed in the other three species. This system is an opportunity to study how far the fine-tuning of char- acter displacement among syntopic species can go.

}, issn = {1029-0362}, doi = {10.1080/10236244.2013.796161}, author = {Bernd Kramer} } @article {823, title = {Marked differentiation in a new species of dwarf stonebasher, Pollimyrus cuandoensis sp. nov. (Mormyridae: Teleostei), from a contact zone with two sibling species of the Okavango and Zambezi rivers}, journal = {Journal of Natural History}, year = {2014}, month = {12/2013}, pages = {1 - 35}, issn = {1464-5262}, doi = {10.1080/00222933.2013.807950}, author = {Bernd Kramer and F. Herman van der Bank and Michael Wink} }