02247nas a2200373   4500008004100000020001400041245011300055210006900168260000800237300001000245490000700255520117200262653002701434653001901461653001801480653001701498653002201515653003601537653002201573653001301595653002301608653001601631653002001647653001501667653001601682653002301698653002501721653001601746100001501762700001801777700002301795700002101818856003401839       2009                        eng d  a0022-111200aThe electric organ discharges of the Petrocephalus species (Teleostei: Mormyridae) of the Upper Volta System0 aelectric organ discharges of the Petrocephalus species Teleostei  cJan  a54-760 v743 a<p>In this study, a first comparative investigation of all four species of Petrocephalus (P. bovei, P. bane, P. soudanensis and P. cf. pallidomaculatus) present in the Upper Volta system and their electric organ discharges (EOD) was conducted. It was found that P. bovei was the most widespread (in terms of habitat use), but in several places P. bovei, P. soudanensis and P. cf. pallidomaculatus occurred syntopically. All species emitted a triphasic signal, and with very few exceptions, the Petrocephalus species of the Upper Volta system could clearly be identified on the basis of their EOD waveforms. The most obvious differences between species in EOD waveforms were in amplitude of the last phase, total duration and fast Fourier transformation (FFT) peak frequency. No sexual dimorphism was present in the EOD of any species although external dimorphism, i.e. an indentation at the base of the anal fin of mature males, was common. The EOD waveform diversity in the Upper Volta principally resembled that found in four sympatric Petrocephalus species from the OgoouE system (Gabon) and might play a role in species recognition and speciation processes.</p>
10aactive electrolocation10acentral-africa10acommunication10aeod waveform10afishes mormyridae10agnathonemus-petersii mormyridae10aosteoglossomorpha10apendjari10apollimyrus-isidori10arecognition10asex-differences10aspeciation10avariability10awater conductivity10aweakly electric fish10awest africa1 aMoritz, T.1 aEngelmann, J.1 aLinsenmair, K., E.1 avon der Emde, G.  u<Go to ISI>://00026251690000403504nas a2200349   4500008004100000020001400041245015000055210006900205260000800274300001400282490000700296520244700303653002302750653000902773653001802782653002902800653003602829653001802865653001202883653002202895653001602917653001402933653002502947653002702972653001502999653001403014100002403028700002203052700002503074700002103099856003403120       2008                        eng d  a1010-061X00aDifferentiation of morphology, genetics and electric signals in a region of sympatry between sister species of African electric fish (Mormyridae)0 aDifferentiation of morphology genetics and electric signals in a  cJul  a1030-10450 v213 a<p>Mormyrid fishes produce and sense weak electric organ discharges (EODs) for object detection and communication, and they have been increasingly recognized as useful model organisms for studying signal evolution and speciation. EOD waveform variation can provide important clues to sympatric species boundaries between otherwise similar or morphologically cryptic forms. Endemic to the watersheds of Gabon (Central Africa), Ivindomyrus marchei and Ivindomyrus opdenboschi are morphologically similar to one another. Using morphometric, electrophysiological and molecular characters [cytochrome b sequences and amplified fragment length polymorphism (AFLP) genotypes], we investigated to what extent these nominal mormyrid species have diverged into biological species. Our sampling covered the known distribution of each species with a focus on the Ivindo River, where the two taxa co-occur. An overall pattern of congruence among datasets suggests that I. opdenboschi and I. marchei are mostly distinct. Electric signal analysis showed that EODs of I. opdenboschi tend to have a smaller initial head-positive peak than those of I. marchei, and they often possess a small third waveform peak that is typically absent in EODs of I. marchei. Analysis of sympatric I. opdenboschi and I. marchei populations revealed slight, but significant, genetic partitioning between populations based on AFLP data (F-ST approximate to 0.04). Taken separately, however, none of the characters we evaluated allowed us to discriminate two completely distinct or monophyletic groups. Lack of robust separation on the basis of any single character set may be a consequence of incomplete lineage sorting due to recent ancestry and/or introgressive hybridization. Incongruence between genetic datasets in one individual, which exhibited a mitochondrial haplotype characteristic of I. marchei but nevertheless fell within a genetic cluster of I. opdenboschi based on AFLP genotypes, suggests that a low level of recent hybridization may also be contributing to patterns of character variation in sympatry. Nevertheless, despite less than perfect separability based on any one dataset and inconclusive evidence for complete reproductive isolation between them in the Ivindo River, we find sufficient evidence to support the existence of two distinctive species, I. opdenboschi and I. marchei, even if not &rsquo;biological species&rsquo; in the Mayrian sense.</p>
10aadaptive radiation10aaflp10aelectric fish10aelectric organ discharge10agnathonemus-petersii mormyridae10aintrogression10amarkers10amitochondrial-DNA10amormyroidea10aphylogeny10apopulation-structure10areproductive isolation10aspeciation10ateleostei1 aLavoué, Sébastien1 aSullivan, John, P1 aArnegard, Matthew, E1 aHopkins, Carl, D  u<Go to ISI>://000256687100010