01832nas a2200169 4500008004100000245008100041210006900122260001300191300001400204490000800218520128400226100002501510700002901535700002201564700002301586856005301609 2016 eng d00aElectric fish genomics: progress, prospects, and new tools for neuroethology0 aElectric fish genomics progress prospects and new tools for neur bElsevier a259–2720 v1103 a

Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10 years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.

1 aPitchers, William, R1 aConstantinou, Savvas, J.1 aLosilla, Mauricio1 aGallant, Jason, R. uhttps://doi.org/10.1016/j.jphysparis.2016.10.00302556nas a2200277 4500008004100000022002500041245011800066210006900184260001600253300001000269490000800279520169400287653002801981653001302009653002002022653002602042653002602068653001302094100001702107700002102124700002302145700001902168700002102187700002202208856004802230 2016 eng d a0378-1909, 1573-513300aReproduction and development in some species of the weakly electric genus Campylomormyrus (Mormyridae, Teleostei)0 aReproduction and development in some species of the weakly elect cDec-07-2016 a49-680 v1003 a

Reproduction in captivity of four species of the mormyrid genus Campylomormyrus was investigated. Cyclical reproduction was provoked by changing water conductivity (C) alone: decreasing C led to gonadal recrudescence, an increase induced gonad regression. Data on the reproduction and development of three species are presented. All three species are indeterminate fractional spawners. Spawning intervals ranged from 6 to 66 days in C. rhynchophorus, 10–75 days in C. tshokwe, and 18 days in C. compressirostris (calculated values). Fecundities (eggs per fractional spawning) ranged from 70 to 1570 eggs in C. rhynchophorus, 100–1192 in C. tshokwe, and 38–246 in C. compressirostris. Spawnings/ovipositions occurred during the second half of the night; no parental care was observed; no special spawning substrates were necessary. C. compressirostris successfully spawned in breeding groups, C. rhynchophorus as pair. Agonistic behavior in the C. tshokwe pair forced us to divide the breeding tank; therefore, only ovipositions occurred. However, injection of an artificial GnRH hormone allowed us to obtain ripe eggs and sperm and to perform successful artificial reproduction. All three species produce yolky, slightly sticky eggs. Egg diameter ranges from 2.3–3.0 mm. Hatching occurred on day 3, feeding started on day 11. Transition from larval to juvenile stage occurred at around 20 mm total length (TL). At this size C. rhynchophorus developed a higher body than the two other species and differences between the species in the melanin pigmentation of the unpaired fins occurred. Between 32 and 35 mm TL the upper and lower jaws started to elongate.

10aArtificial reproduction10aBehavior10aCampylomormyrus10aCyclical reproduction10aEnvironmental factors10aOntogeny1 aNguyen, Linh1 aPaul, Christiane1 aMamonekene, Victor1 aBartsch, Peter1 aTiedemann, Ralph1 aKirschbaum, Frank uhttp://dx.doi.org/10.1007/s10641-016-0554-102502nas a2200145 4500008004100000022001300041245011400054210006900168260001600237520196500253100002202218700002902240700002102269856006602290 2016 eng d a0928425700aObject discrimination through active electrolocation: Shape recognition and the influence of electrical noise0 aObject discrimination through active electrolocation Shape recog cJan-12-20163 a

The weakly electric fish Gnathonemus petersii can recognise objects using active electrolocation. Here, we tested two aspects of object recognition; first whether shape recognition might be influenced by movement of the fish, and second whether object discrimination is affected by the presence of electrical noise from conspecifics. (i) Unlike other object features, such as size or volume, no parameter within a single electrical image has been found that encodes object shape. We investigated whether shape recognition might be facilitated by movement-induced modulations (MIM) of the set of electrical images that are created as a fish swims past an object. Fish were trained to discriminate between pairs of objects that either created similar or dissimilar levels of MIM of the electrical images. As predicted, the fish were able to discriminate between objects up to a longer distance if there was a large difference in MIM between the objects than if there was a small difference. This supports an involvement of MIMs in shape recognition but the use of other cues cannot be excluded. (ii) Electrical noise might impair object recognition if the noise signals overlap with the EODs of an electrolocating fish. To avoid jamming, we predicted that fish might employ pulsing strategies to prevent overlaps. To investigate the influence of electrical noise on discrimination performance, two fish were tested either in the presence of a conspecific or of playback signals and the electric signals were recorded during the experiments. The fish were surprisingly immune to jamming by conspecifics: While the discrimination performance of one fish dropped to chance level when more than 22% of its EODs overlapped with the noise signals, the performance of the other fish was not impaired even when all its EODs overlapped. Neither of the fish changed their pulsing behaviour, suggesting that they did not use any kind of jamming avoidance strategy.

1 aSchumacher, Sarah1 ade Perera, Theresa, Burt1 avon der Emde, G. uhttp://linkinghub.elsevier.com/retrieve/pii/S092842571630030402153nas a2200169 4500008004100000022001400041245015600055210006900211260001600280300000800296490000900304520155700313100001801870700002401888700001401912856005701926 2016 eng d a1175-532600aElectric organ discharges of South African Marcusenius species (Teleostei: Mormyridae) and their effectiveness as indicators of local species diversity0 aElectric organ discharges of South African Marcusenius species T cMay-11-2018 a3670 v42003 a

Recent morphological and genetic studies have revealed two new species of snoutfish in South Africa, Marcusenius caudisquamatus and M. krameri, which had been confused with M. pongolensis, the South African bulldog fish. All known mormyriform fish are nocturnal and emit electric organ discharges (EODs) for communication that are characteristic for their species. This paper examines whether or not the EODs of these three closely-related South African species can be differentiated from each other. An EOD pulse of a bulldog fish consists of a head-positive phase P, followed by a head-negative phase N of short duration. We measured and compared six variables of the EOD pulse waveform for South African samples for the three species from different locations using MANOVA, ANOVA and Discriminant Analysis, with M. devosi from Kenya as an outgroup. The EOD waveforms, normalized to the same P-phase amplitude, varied significantly from each other in four variables, most strongly in the amplitude of the N phase and the duration of the P phase. In two species, M. devosi and M. krameri, there was no evidence of difference between sexes, in contrast to M. pongolensis and M. caudisquamatus whose male pulses were of longer duration. M. devosi and M. krameri were statistically significantly independent of each other and of any other group studied. By contrast, the M. pongolensis specimens from different locations showed a high degree of variability amongst each other, including significant separation, and overlap with M. caudisquamatus.

1 aKramer, Bernd1 aMaake, Pholoshi, A.1 aGon, Ofer uhttp://biotaxa.org/Zootaxa/issue/view/zootaxa.4200.302878nas a2200157 4500008004100000022001400041245008600055210006900141260001600210520234200226100001602568700003102584700001902615700001802634856006802652 2016 eng d a0270-647400aSensory flow as a basis for a novel distance cue in freely behaving electric fish0 aSensory flow as a basis for a novel distance cue in freely behav cNov-24-20163 a

ABSTRACT

The sensory input that an animal receives is directly linked to its motor activity. Behavior thus enables animals to influence their sensory input, a concept referred to as active sensing. How such behavior can serve as a scaffold for generating sensory information is of general scientific interest. In this article, we investigate how behavior can shape sensory information by using some unique features of the sensorimotor system of the weakly electric fish.

Based on quantitative behavioral characterizations and computational reconstruction of sensory input, we show how electrosensory flow is actively created during highly patterned, spontaneous behavior in Gnathonemus petersii. The spatiotemporal structure of the sensory input provides information for the computation of a novel distance cue, which allows for a continuous estimation of distance. This has significant advantages over previously known non-dynamic distance estimators as determined from electric image blur.

Our investigation of the sensorimotor interactions in pulsatile electrolocation show, for the first time, that the electrosensory flow contains behaviorally relevant information only accessible through active behavior. As patterned sensory behaviors are a shared feature of (active) sensory systems, our results have general implications for the understanding of (active) sensing, with the proposed sensory flow based-measure being potentially pertinent to a broad range of sensory modalities.

SIGNIFICANCE STATEMENT

Acquisition of sensory information depends on motion, as either an animal or its sensors move. Behavior can thus actively influence the sensory flow, and in this way, behavior can be seen as a manifestation of the brain's integrative functions. The properties of the active pulsatile electrolocation system in Gnathonemus petersii allow for the sensory input to be computationally reconstructed, enabling us to link the informational content of spatiotemporal sensory dynamics to behavior. Our study reveals a novel sensory cue for estimating depth that is actively generated by the fishes' behavior. The physical and behavioral similarities between electrolocation and other active sensory systems suggest that this may be a mechanism shared by (active) sensory systems.

1 aHofmann, V.1 aSanguinetti-Scheck, J., I.1 aGomez-Sena, L.1 aEngelmann, J. uhttp://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.1361-16.201601997nas a2200229 4500008004100000022001300041245008100054210006900135260001600204520128400220653001101504653001801515653001901533653001301552653002001565653001601585100002601601700002901627700002201656700002301678856006601701 2016 eng d a0928425700aElectric Fish Genomics: Progress, Prospects, and New Tools for Neuroethology0 aElectric Fish Genomics Progress Prospects and New Tools for Neur cJan-10-20163 a

Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10 years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.

10aCRISPR10aelectric fish10agenome editing10agenomics10atranscriptomics10atransgenics1 aPitchers, William, R.1 aConstantinou, Savvas, J.1 aLosilla, Mauricio1 aGallant, Jason, R. uhttp://linkinghub.elsevier.com/retrieve/pii/S092842571630007900914nas a2200121 4500008004100000245010500041210006900146260001600215520048500231100001800716700001500734856004300749 2016 eng d00aAnal-fin ray morphology indicates sexual maturity in Brevimyrus niger (Teleostei, Mormyridae)0 aAnalfin ray morphology indicates sexual maturity in iBrevimyrus  cJan-10-20163 a

This osteological survey of 249 specimens of Brevimyrus niger ranging in size from 44 to 137 mm standard length (LS) demonstrated that developmental changes in anal-fin morphology can serve as a predictor of sexual maturity in this species. Anal-fin ray bases begin to expand when fish reach c. 90 mm LS at which size and above there were roughly equal numbers of individuals observed with expanded and unmodified anal-fin bases, reflecting a 1:1 sex ratio.

1 aStell, S., K.1 aMoller, P. uhttp://doi.wiley.com/10.1111/jfb.1316303433nas a2200181 4500008004100000022001400041245011700055210006900172260002000241300001600261490000700277520282600284100001803110700001103128700002203139700002203161856006803183 2016 eng d a0270-647400aBehavioral and Single-Neuron Sensitivity to Millisecond Variations in Temporally Patterned Communication Signals0 aBehavioral and SingleNeuron Sensitivity to Millisecond Variation cFeb-16-20162220 a8985 - 90000 v363 a

In many sensory pathways, central neurons serve as temporal filters for timing patterns in communication signals. However, how a population of neurons with diverse temporal filtering properties codes for natural variation in communication signals is unknown. Here we addressed this question in the weakly electric fish Brienomyrus brachyistius, which varies the time intervals between successive electric organ discharges to communicate. These fish produce an individually stereotyped signal called a scallop, which consists of a distinctive temporal pattern of ∼8–12 electric pulses. We manipulated the temporal structure of natural scallops during behavioral playback and in vivo electrophysiology experiments to probe the temporal sensitivity of scallop encoding and recognition. We found that presenting time-reversed, randomized, or jittered scallops increased behavioral response thresholds, demonstrating that fish's electric signaling behavior was sensitive to the precise temporal structure of scallops. Next, using in vivo intracellular recordings and discriminant function analysis, we found that the responses of interval-selective midbrain neurons were also sensitive to the precise temporal structure of scallops. Subthreshold changes in membrane potential recorded from single neurons discriminated natural scallops from time-reversed, randomized, and jittered sequences. Pooling the responses of multiple neurons improved the discriminability of natural sequences from temporally manipulated sequences. Finally, we found that single-neuron responses were sensitive to interindividual variation in scallop sequences, raising the question of whether fish may analyze scallop structure to gain information about the sender. Collectively, these results demonstrate that a population of interval-selective neurons can encode behaviorally relevant temporal patterns with millisecond precision.

SIGNIFICANCE STATEMENT The timing patterns of action potentials, or spikes, play important roles in representing information in the nervous system. However, how these temporal patterns are recognized by downstream neurons is not well understood. Here we use the electrosensory system of mormyrid weakly electric fish to investigate how a population of neurons with diverse temporal filtering properties encodes behaviorally relevant input timing patterns, and how this relates to behavioral sensitivity. We show that fish are behaviorally sensitive to millisecond variations in natural, temporally patterned communication signals, and that the responses of individual midbrain neurons are also sensitive to variation in these patterns. In fact, the output of single neurons contains enough information to discriminate stereotyped communication signals produced by different individuals.

1 aBaker, C., A.1 aMa, L.1 aCasareale, C., R.1 aCarlson, Bruce, A uhttp://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.0648-16.201602253nas a2200169 4500008004100000022001400041245012600055210006900181260001600250300001100266520166400277100002101941700002201962700002301984700002102007856005502028 2016 eng d a0022-284400aEvidence for Non-neutral Evolution in a Sodium Channel Gene in African Weakly Electric Fish (Campylomormyrus, Mormyridae)0 aEvidence for Nonneutral Evolution in a Sodium Channel Gene in Af cJan-08-2016 a1–173 a

Voltage-gated sodium channels, Nav1, play a crucial role in the generation and propagation of action potentials and substantially contribute to the shape of their rising phase. The electric organ discharge (EOD) of African weakly electric fish (Mormyroidea) is the sum of action potentials fired from all electrocytes of the electric organ at the same time and hence voltage-gated sodium channels are one factor—together with the electrocyte’s morphology and innervation pattern—that determines the properties of these EODs. Due to the fish-specific genome duplication, teleost fish possess eight copies of sodium channel genes (SCN), which encode for Nav1 channels. In mormyroids, SCN4aa is solely expressed in the electrocytes of the adult electric organ. In this study, we compared entire SCN4aa sequences of six species of the genus Campylomormyrus and identified nonsynonymous substitutions among them. SCN4aa in Campylomormyrus exhibits a much higher evolutionary rate compared to its paralog SCN4ab, whose expression is not restricted to the electric organ. We also found evidence for strong positive selection on the SCN4aa gene within Mormyridae and along the lineage ancestral to the Mormyridae. We have identified sites at which all nonelectric teleosts are monomorphic in their amino acid, but mormyrids have different amino acids. Our findings confirm the crucial role of SCN4aa in EOD evolution among mormyrid weakly electric fish. The inferred positive selection within Mormyridae makes this gene a prime candidate for further investigation of the divergent evolution of pulse-type EODs among closely related species.

1 aPaul, Christiane1 aKirschbaum, Frank1 aMamonekene, Victor1 aTiedemann, Ralph uhttp://link.springer.com/10.1007/s00239-016-9754-801591nas a2200133 4500008004100000245012000041210006900161260001600230490000600246520110100252100002201353700002201375856006001397 2016 eng d00aDetection of transient synchrony across oscillating receptors by the central electrosensory system of mormyrid fish0 aDetection of transient synchrony across oscillating receptors by cSep-06-20170 v53 a

Recently, we reported evidence for a novel mechanism of peripheral sensory coding based on oscillatory synchrony. Spontaneously oscillating electroreceptors in weakly electric fish (Mormyridae) respond to electrosensory stimuli with a phase reset that results in transient synchrony across the receptor population (Baker et al., 2015). Here, we asked whether the central electrosensory system actually detects the occurrence of synchronous oscillations among receptors. We found that electrosensory stimulation elicited evoked potentials in the midbrain exterolateral nucleus at a short latency following receptor synchronization. Frequency tuning in the midbrain resembled peripheral frequency tuning, which matches the intrinsic oscillation frequencies of the receptors. These frequencies are lower than those in individual conspecific signals, and instead match those found in collective signals produced by groups of conspecifics. Our results provide further support for a novel mechanism for sensory coding based on the detection of oscillatory synchrony among peripheral receptors.

1 aVélez, Alejandro1 aCarlson, Bruce, A uhttp://elifesciences.org/lookup/doi/10.7554/eLife.1685102604nas a2200217 4500008004100000245013800041210006900179260001200248300001200260490000900272520191100281653001102192653001702203653000902220653002402229653001502253653002202268653002002290100002402310856005202334 2016 eng d00aPetrocephalus leo, a new species of African electric fish (Osteoglossomorpha: Mormyridae) from the Oubangui River basin (Congo basin)0 aPetrocephalus leo a new species of African electric fish Osteogl c06/2016 a319-3300 v41213 a

A new species of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha: Mormyridae: Petrocephalinae) is described from the Oubangui (Ubangi) River basin, the principal right-bank tributary of the Congo River. Petrocephalus leo sp. nov. is one of the most distinctive species of Petrocephalus as it combines (among other characteristics) the absence of electroreceptive rosettes on the head with a unique melanin pattern. Only four other species of Petrocephalus lack all electroreceptive rosettes: Petrocephalus microphthalmus, Petrocephalus haullevillii, Petrocephalus schoutedeni, and Petrocephalus zakoni. Petrocephalus leo sp. nov. can be distinguished from these four species in having a distinctive black mark at the base of the pectoral fins (versus absent in P. microphthalmus, P. haullevillii and P. schoutedeni) and no subdorsal black mark (versus present in P. zakoni). A phylogenetic analysis using mitochondrial cytochrome b gene sequences shows haplotypes of P. leo sp. nov. are distinct, but are unexpectedly nested within P. zakoni haplotypes, making this latter species paraphyletic. To investigate this conflict between morphology and mitochondrial cytochrome b, a nuclear marker, the first intron of the gene coding for the S7 ribosomal protein, was sequenced. The presence of four diagnostic indels between P. zakoni and P. leo sp. nov. sequences supports the reciprocal monophyly of these two species. This is the first reported case of conflict between morphology and mitochondrial phylogeny within the genus Petrocephalus. Finally, three species of Petrocephalus are reported for the first time from the Oubangui region bringing the total of Petrocephalus species in this region to 12.

10aAfrica10acytochrome b10afish10amolecular phylogeny10amorphology10anuclear S7 intron10aPetrocephalinae1 aLavoué, Sébastien uhttps://mormyrids.efishgenomics.com/en/node/50102166nas a2200121 4500008004100000022001300041245012900054210006900183260001600252520169100268100001901959856006601978 2016 eng d a1687428500aGrowth pattern and natural mortality of elephant fishes (Mormyrus kannume, Mormyridae) in the Damietta branch of Nile, Egypt0 aGrowth pattern and natural mortality of elephant fishes Mormyrus cJan-05-20163 a

The present study sheds light on the growth pattern of the elephant snout fish (Mormyrus kannume, Mormyridae) in the Damietta branch of the Nile during the period from January to December 2010. This is done through studying the biometric characters, length–weight relationship, condition factors, growth performance index as well as the natural mortality. The linear regression for 15 morphometric characters in total length and 4 morphometric characters in head length was applied. The higher coefficient of the characters’ determinations which fit best was also applied. Five meristic characters were determined (dorsal fin rays, 49–69; pectoral fin rays, 12–15; ventral fin rays, 6; anal fin rays, 17–21 and vertebrae, 49–52). Fish length varied between 14.0 cm and 43.0 cm TL with a modal length range from 19 to 22 cm representing 61.36% of the fish sample. A length–weight relationship using the total weight was found to be Log W = −2.2218 + 3.063 Log L (R2 = 0.997) and using the gutted weight was Log W = −2.1549 + 3.003 Log L (R2 = 0.995) hence exhibiting isometric growth. The average condition factors for different lengths were 0.76 ± 0.06. The chi-square of the overall sex ratio (male:female = 1:0.42) was significant at P < 0.01. The life span of this species is five years, with individuals of two years of age dominating the population. The different growth parameters were estimated at (K = 0.141, to = −0.271, L∞ = 80.65 cm, W∞ = 4151 g, ФL = 2.96 and ФW = 1.56). The natural mortality was 0.34, the M/K ratio was 2.38 and the variation of M by age model was also computed.

1 aRagheb, Evelyn uhttp://linkinghub.elsevier.com/retrieve/pii/S168742851630019X02056nas a2200265 4500008004100000022001300041245015000054210006900204260001600273520114000289653002001429653002801449653002001477653001501497653002801512653002501540100002301565700002201588700002201610700002701632700002301659700002101682700002101703856006601724 2016 eng d a1055790300aSpecies delimitation and phylogenetic relationships in a genus of African weakly-electric fishes (Osteoglossiformes, Mormyridae, Campylomormyrus)0 aSpecies delimitation and phylogenetic relationships in a genus o cJan-04-20163 a

African weakly-electric fishes (Mormyridae) are able to communicate through species-specific electric signals; this feature might have favoured the evolutionary radiation observed in this family (over 200 species) by acting as an effective pre-zygotic isolation mechanism. In the present study we used mitochondrial (cytb) and nuclear (rps7, scn4aa) markers in order to reconstruct a species-phylogeny and identify species boundaries for the genus Campylomormyrus, by applying inference methods based on the multispecies coalescent model. Additionally, we employed 16 microsatellite markers, landmark-based morphometric measurements, and electro-physiological analyses as independent lines of evidence to the results obtained from the sequence data. The results show that groups that are morphologically different are also significantly divergent at the genetic level, whereas morphologically similar groups, displaying dissimilar electric signals, do not show enough genetic diversity to be considered separate species. Furthermore, the data confirm the presence of a yet undescribed species within the genus Campylomormyrus.

10aCampylomormyrus10aGeometric morphometrics10aMicrosatellites10aMormyridae10aMultispecies-coalescent10aSpecies-delimitation1 aLamanna, Francesco1 aKirschbaum, Frank1 aErnst, Anja, R.R.1 aFeulner, Philine, G.D.1 aMamonekene, Victor1 aPaul, Christiane1 aTiedemann, Ralph uhttp://linkinghub.elsevier.com/retrieve/pii/S105579031630078102614nas a2200181 4500008004100000022001400041245015700055210006900212260001200281300001400293490000700307520197000314100002702284700001402311700001602325700002102341856007002362 2016 eng d a0936-990200aMarcusenius kaninginii, a new species of elephantfish from the Lowa River basin, Democratic Republic of the Congo (Osteoglossiformes: Mormyridae)0 aiMarcusenius kaninginiii a new species of elephantfish from the  c03/2016 a341–3520 v263 a

Marcusenius kaninginii, a new Marcusenius species with eight large circumpeduncular scales, is described from the Lowa River, a right bank tributary of the Lualaba (Upper Congo basin). It is distinguished from all other Mar- cusenius species with eight circumpeduncular scales by the following unique combination of characters: 43-47 lateral line scales; 18-23 dorsal-fin rays; 27-30 anal-fin rays; 42-44 vertebrae; a relatively shallow body at the anterior base of the anal fin (depth 25.0-28.6 % SL); a deep caudal peduncle (39-57 % of caudal peduncle length); and a short pectoral fin (15.5-19.1 % SL). Additionally, it has a typical dark-brown body coloration with a black transversal bar between the anterior parts of the dorsal and anal fins, and a black horizontal band along the lat- eral line from just behind the opercle up to the transversal bar.


Marcusenius kaninginii, une nouvelle espèce de Marcusenius à huit écailles autour du pédoncule caudal, est décrite de la rivière Lowa, un affluent de la rive droite du Lualaba (bassin du Congo Supérieur). Il se distingue des autres Marcusenius à huit écailles autour du pédoncule caudal par la combinaison unique des caractères suivants: 43-47 écailles sur la ligne latérale; 18-23 rayons à la dorsale; 27-30 rayons à l’anale; 42-44 vertèbres; corps relativement moins élevé à la base antérieure de la nageoire anale (hauteur 25,0-28,6 % LS); un pédoncule caudal haut, (39- 57 % de la longueur du pédoncule caudal); et une nageoire pectorale courte (15,5-19,1 % LS). De plus, il présente une coloration corporelle typique noire-brunâtre avec une bande transversale noire entre les parties antérieures des nageoires dorsale et anale ainsi qu’une bande noire horizontale le long de la ligne latérale allant de l’opercule jusqu’à la bande transversale.

1 aKisekelwa, Tchalondawa1 aBoden, G.1 aSnoeks, Jos1 aVreven, Emmanuel uhttps://pfeil-verlag.de/wp-content/uploads/2016/07/ief26_4_04.pdf02046nas 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/10.2989/16085914.2015.113785501819nas a2200169 4500008004100000020002200041245009300063210006900156260004400225300001400269520123700283100002101520700001801541700002101559700001401580856005501594 2016 eng d a978-3-319-25490-600aMatched Filtering in African Weakly Electric Fish: Two Senses with Complementary Filters0 aMatched Filtering in African Weakly Electric Fish Two Senses wit aChambSpringer International Publishing a237 - 2633 a

African weakly electric fish live nocturnally in tropical freshwater streams. To sense their surroundings, they have developed a highly specialized system of two senses, which allows them to perceive nearby objects at high precision with an active electric sense and to detect large, fast-moving objects with their visual sense at greater distances. Both senses are highly specialized and are equipped with matched filters for efficient detection and analysis of relevant object features and for neglecting unimportant items. Active electrolocation in the near field involves the production of an electric signal, which serves as a carrier for sensory information. This signal and the resulting electric field around the fish are shaped by the fish’s body and its internal structure. The electric skin properties and the accessory structures of the electroreceptor organs further filter
the signal and form two electroreceptive foveae. In contrast, the visual system is adapted for detecting large objects at longer distances. A grouped retina forms a visual matched filter, which filters out small, nearby objects but efficiently detects fast-moving distant objects even under noisy and dim light conditions.

1 avon der Emde, G.1 aWarrant, Eric1 avon der Emde, G.1 aRuhl, Tim uhttp://link.springer.com/10.1007/978-3-319-25492-002363nas a2200145 4500008004100000022001400041245013300055210006900188260001600257300001200273490000800285520184500293100002202138856005702160 2016 eng d a0022-094900aDifferences in electrosensory anatomy and social behavior in an area of sympatry between two species of mormyrid electric fishes0 aDifferences in electrosensory anatomy and social behavior in an  cApr-11-2016 a31 - 430 v2193 a

Sensory systems play a key role in social behavior by mediating the detection and analysis of communication signals. In mormyrid fishes, electric signals are processed within a dedicated sensory pathway, providing a unique opportunity to relate sensory biology to social behavior. Evolutionary changes within this pathway led to new perceptual abilities that have been linked to increased rates of signal evolution and species diversification in a lineage called ‘clade A’. Previous field observations suggest that clade-A species tend to be solitary and territorial, whereas non-clade-A species tend to be clustered in high densities suggestive of schooling or shoaling. To explore behavioral differences between species in these lineages in greater detail, I studied population densities, social interactions, and electric signaling in two mormyrid species, Gnathonemus victoriae (clade A) and Petrocephalus degeni (non-clade A), from Lwamunda Swamp, Uganda. Petrocephalus degeni was found at higher population densities, but intraspecific diversity in electric signal waveform was greater in G. victoriae. In the laboratory, G. victoriae exhibited strong shelter-seeking behavior and competition for shelter, whereas P. degeni were more likely to abandon shelter in the presence of conspecifics as well as electric mimics of signaling conspecifics. In other words, P. degeni exhibited social affiliation whereas G. victoriae exhibited social competition. Further, P. degeni showed correlated electric signaling behavior whereas G. victoriae showed anti-correlated signaling behavior. These findings extend previous reports of social spacing, territoriality, and habitat preference among mormyrid species, suggesting that evolutionary divergence in electrosensory processing relates to differences in social behavior.

1 aCarlson, Bruce, A uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.12772003856nas a2200277 4500008004100000022001400041245013400055210006900189260001600258300001400274490000800288520299800296653003003294653000803324653002903332653000803361653002503369653001503394653001403409653001103423653002503434100002203459700002403481700002103505856005203526 2016 eng d a1313-298900aCryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa0 aiCryptomyrusi a new genus of Mormyridae Teleostei Osteoglossomor cAug-02-2016 a117 - 1500 v5613 a

Abstract
We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In C. ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.

Résumé
Nous avons démontré avec des marqueurs mitochondriaux et nucléaires que trois spécimens de poissons mormyridés faiblement électriques, collectés à trois localités au Gabon sur une période de 13 ans, forment une lignée inconnue au sein de la sous famille des Mormyrinae dont nous avons déterminé la position phylogénétique. Nous décrivons un nouveau genre et deux nouvelles espèces pour ces trois spécimens. Cryptomyrus, nouveau genre, se distingue des autres genres de mormyridés par une combinaison de caractères de l’écaillure, morphométriques, et dentaires. Cryptomyrus ogoouensis, nouvelle espèce, se distingue de sa seule espèce congénérique par sa nageoire anale qui commence nettement en avant de sa nageoire dorsale, son pédoncule caudal gracile et les lobes de sa nageoire caudale pratiquement aussi longs que son pédoncule caudal. Chez Cryptomyrus ona, nouvelle espèce, la nageoire anale commence légèrement en avant de l’origine de la nageoire dorsale, le pédoncule caudal est large, et les lobes de la nageoire caudale sont plus courts que le pédoncule caudal. La découverte ininterrompue de nouveaux taxa dans le «clade de basse Guinée» des Mormyridae illustre notre connaissance incomplète de la diversité des poissons de l’ouest de l’Afrique centrale. Nous présentons une clé révisée des genres de Mormyridae de basse Guinée.

10aAfrican freshwater fishes10aDNA10aelectric organ discharge10aEOD10aintegrative taxonomy10aMormyrinae10aphylogeny10ararity10aweakly electric fish1 aSullivan, John, P1 aLavoué, Sébastien1 aHopkins, Carl, D uhttp://zookeys.pensoft.net/articles.php?id=7137