@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} }