02046nas a2200229 4500008004100000022001400041245010400055210006900159260001600228300001100244520130700255653001201562653003001574653002801604653001501632653001901647653001501666100001801681700002901699700001801728856007001746 2016 eng d a1608-591400aMarcusenius desertus sp. nov. (Teleostei: Mormyridae), a mormyrid fish from the Namib desert0 aiMarcusenius desertusi sp nov Teleostei Mormyridae a mormyrid fi cJul-03-2016 a1 - 183 a

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.

10aecology10aelectric organ discharges10agenetic differentiation10amorphology10aphylogeography10aspeciation1 aKramer, Bernd1 avan der Bank, F., Herman1 aWink, Michael uhttp://www.tandfonline.com/doi/full/10.2989/16085914.2015.113785502247nas 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

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.

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://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

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 ’biological species’ in the Mayrian sense.

10aadaptive radiation10aaflp10aelectric fish10aelectric organ discharge10agnathonemus-petersii mormyridae10aintrogression10amarkers10amitochondrial-DNA10amormyroidea10aphylogeny10apopulation-structure10areproductive isolation10aspeciation10ateleostei1 aLavoué, Sébastien1 aSullivan, John, P1 aArnegard, Matthew, E1 aHopkins, Carl, D u://000256687100010