01694nas a2200217 4500008004100000245006500041210006500106260001300171300001600184490000700200520103900207100001901246700002001265700001901285700002401304700001901328700001301347700002301360700002101383856007201404 2018 eng d00aElectrostatic tuning of a potassium channel in electric fish0 aElectrostatic tuning of a potassium channel in electric fish bElsevier a2094–21020 v283 a

Molecular variation contributes to the evolution of adaptive phenotypes, though it is often difficult to understand precisely how. The adaptively significant electric organ discharge behavior of weakly electric fish is the direct result of biophysical membrane properties set by ion channels. Here, we describe a voltage-gated potassium-channel gene in African electric fishes that is under positive selection and highly expressed in the electric organ. The channel produced by this gene shortens electric organ action potentials by activating quickly and at hyperpolarized membrane potentials. The source of these properties is a derived patch of negatively charged amino acids in an extracellular loop near the voltage sensor. We demonstrate that this negative patch acts by contributing to the global surface charge rather than by local interactions with specific amino acids in the channel's extracellular face. We suggest a more widespread role for this loop in the evolutionary tuning of voltage-dependent channels.

1 aSwapna, Immani1 aGhezzi, Alfredo1 aYork, Julia, M1 aMarkham, Michael, R1 aHalling, Brent1 aLu, Ying1 aGallant, Jason, R.1 aZakon, Harold, H uhttps://www.sciencedirect.com/science/article/pii/S096098221830614602027nas a2200205 4500008004100000022001400041245012600055210006900181260001600250490000700266520132500273653001701598653001901615653001701634653001401651653001301665100002101678700002401699856009801723 2018 eng d a1679-622500aA review of the systematic biology of fossil and living bony-tongue fishes, Osteoglossomorpha (Actinopterygii: Teleostei)0 areview of the systematic biology of fossil and living bonytongue cJan-01-20180 v163 a

The bony-tongue fishes, Osteoglossomorpha, have been the focus of a great deal of morphological, systematic, and evolutionary study, due in part to their basal position among extant teleostean fishes. This group includes the mooneyes (Hiodontidae), knifefishes (Notopteridae), the abu (Gymnarchidae), elephantfishes (Mormyridae), arawanas and pirarucu (Osteoglossidae), and the African butterfly fish (Pantodontidae). This morphologically heterogeneous group also has a long and diverse fossil record, including taxa from all continents and both freshwater and marine deposits. The phylogenetic relationships among most extant osteoglossomorph families are widely agreed upon. However, there is still much to discover about the systematic biology of these fishes, particularly with regard to the phylogenetic affinities of several fossil taxa, within Mormyridae, and the position of Pantodon. In this paper we review the state of knowledge for osteoglossomorph fishes. We first provide an overview of the diversity of Osteoglossomorpha, and then discuss studies of the phylogeny of Osteoglossomorpha from both morphological and molecular perspectives, as well as biogeographic analyses of the group. Finally, we offer our perspectives on future needs for research on the systematic biology of Osteoglossomorpha.

10aBiogeography10aOsteoglossidae10aPaleontology10aphylogeny10aTaxonomy1 aHilton, Eric, J.1 aLavoué, Sébastien uhttp://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252018000300304&lng=en&tlng=en01443nas a2200169 4500008004100000022001400041245011200055210006900167260001600236300001400252490000800266520088300274100001801157700001801175700002501193856005501218 2018 eng d a0012-496600aElectric Organ Discharges of Cyphomyrus petherici (Mormyridae, Osteoglossiformes) from the White Nile Basin0 aElectric Organ Discharges of Cyphomyrus petherici Mormyridae Ost cJan-07-2018 a142 - 1450 v4813 a

The waveform and some characteristics of the electric organ discharges have been studied in 11 individuals of Cyphomyrus petherici, the only representative of the genus in the Nilotic fauna. The discharge is characterized by three to five phases with a prevalence of the second phase in terms of the relative amplitude and a wide variability of the total duration of discharge (from 212 to 558 μs). The comparison of the discharges of the species under study with those in the congeneric species and representatives of the genus Pollimyrus (which previously encompassed C. petherici) demonstrates a general similarity of the C. petherici discharges with those of Cyphomyrus, but not Pollimyrus. This is in agreement with the correspondence of the discharge characteristics observed in other mormyrids to the phylogenetic position and taxonomic status of the species.

1 aBaron, V., D.1 aOrlov, A., A.1 aGolubtsov, Alexander uhttp://link.springer.com/10.1134/S001249661804003802093nas a2200169 4500008004100000245010600041210006900147260001600216490000600232520152800238100001901766700002201785700002001807700002101827700002101848856005401869 2018 eng d00aElectric pulse characteristics can enable species recognition in African weakly electric fish species0 aElectric pulse characteristics can enable species recognition in cJan-12-20180 v83 a

Communication is key to a wide variety of animal behaviours and multiple modalities are often involved in this exchange of information from sender to receiver. The communication of African weakly electric fish, however, is thought to be predominantly unimodal and is mediated by their electric sense, in which species-specific electric organ discharges (EODs) are generated in a context-dependent and thus variable sequence of pulse intervals (SPI). While the primary function of the electric sense is considered to be electrolocation, both of its components likely carry information regarding identity of the sender. However, a clear understanding of their contribution to species recognition is incomplete. We therefore analysed these two electrocommunication components (EOD waveform and SPI statistics) in two sympatric mormyrid Campylomormyrus species. In a set of five playback conditions, we further investigated which components may drive interspecific recognition and discrimination. While we found that both electrocommunication components are species-specific, the cues necessary for species recognition differ between the two species studied. While the EOD waveform and SPI were both necessary and sufficient for species recognition in C. compressirostris males, C. tamandua males apparently utilize other, non-electric modalities. Mapped onto a recent phylogeny, our results suggest that discrimination by electric cues alone may be an apomorphic trait evolved during a recent radiation in this taxon.

1 aNagel, Rebecca1 aKirschbaum, Frank1 aHofmann, Volker1 aEngelmann, Jacob1 aTiedemann, Ralph uhttp://www.nature.com/articles/s41598-018-29132-z