@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 {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 {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 {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 {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 {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} }