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The genus Eigenmannia Jordan et Evermann,1896 includes electric fishes endemic to the Neotropical region with extensive karyotype variability and occurrence of different sex chromosome systems, however, cytogenetic studies within this group are restricted to few species. Here, we describe the karyotypes of Eigenmannia limbata (Schreiner et Miranda Ribeiro, 1903) and E. microstoma (Reinhardt, 1852) and the chromosomal locations of 5S and 18S rDNAs (ribosomal RNA genes) and U2 snDNA (small nuclear RNA gene). Among them, 18S rDNA sites were situated in only one chromosomal pair in both species, and co-localized with 5S rDNA in E. microstoma. On the other hand, 5S rDNA and U2 snRNA sites were observed on several chromosomes, with variation in the number of sites between species under study. These two repetitive DNAs were observed co-localized in one chromosomal pair in E. limbata and in four pairs in E. microstoma. Our study shows a new case of association of these two types of repetitive DNA in the genome of Gymnotiformes.

Eigenmannia desantanai Peixoto, Dutra & Wosiacki, 2015: 393, fig. 7. Paratypes: 2 lots, 19 specimens —NUP 3470, 9 + 1 c&s, 119.8–142.8 mm LEA: Brazil, Mato Grosso, Santo Antônio do Leverger, rio Cuiabá, rio Paraguai basin, 15°58’26”S, 55°56’26”W, Nupélia staff, 24 Oct 2002. NUP 12500, 9, 78.3–106.1 mm LEA: Brazil, Mato Grosso, Barão do Melgaço, rio Cuiabá, baía de Chacororé, rio Paraguai basin, 16°14’58.9”S, 55°52’44.4” W, Nupélia staff, 20 Oct 2003., Published as part of De Oliveira, Rianne C., Ota, Renata R., Deprá, Gabriel C., Zawadzki, Cláudio H., Pavanelli, Carla S. & Da Graça, Weferson J., 2022, Catalog of type specimens of the fish collection of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP), Universidade Estadual de Maringá Paraná, Brazil, pp. 1-43 in Zootaxa 5128 (1) on page 10, DOI: 10.11646/zootaxa.5128.1.1, http://zenodo.org/record/6479497, {"references":["Peixoto, L. A. W., Dutra, G. M. & Wosiacki, W. B. (2015) The electric glass knifefishes of the Eigenmannia trilineata speciesgroup (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zoological Journal of the Linnean Society, 175 (2), 384 - 414. https: // doi. org / 10.1111 / zoj. 12274"]}

Eigenmannia pavulagem Peixoto, Dutra & Wosiacki, 2015: 403, fig. 17. Paratypes: 1 lot, 2 specimens — NUP 17104, 2, 82.7–114.7 mm LEA: Pará, Paragominas, igarapé Paraquequara, tributary of rio Capim, rio Guamá basin, 3°14’50”S, 47°45’50” W, A. Souza, 16 Apr 2003., Published as part of De Oliveira, Rianne C., Ota, Renata R., Deprá, Gabriel C., Zawadzki, Cláudio H., Pavanelli, Carla S. & Da Graça, Weferson J., 2022, Catalog of type specimens of the fish collection of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP), Universidade Estadual de Maringá Paraná, Brazil, pp. 1-43 in Zootaxa 5128 (1) on page 10, DOI: 10.11646/zootaxa.5128.1.1, http://zenodo.org/record/6479497, {"references":["Peixoto, L. A. W., Dutra, G. M. & Wosiacki, W. B. (2015) The electric glass knifefishes of the Eigenmannia trilineata speciesgroup (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zoological Journal of the Linnean Society, 175 (2), 384 - 414. https: // doi. org / 10.1111 / zoj. 12274"]}

A new species of Eigenmannia is described from the Rio Parana (the Grande, Paranapanema and Tiete basins). This new species is distinguished from all congeners by colouration pattern, position of the mouth, relative depth of posterodorsal expansion on infraorbitals 1 + 2, number of teeth, osteological features, number of rows of scales above lateral line (LL) and morphometric data. Comments on the widened cephalic lateral-line canals of Sternopygidae and a dichotomous key to the species of Eigenmannia from the Rio Parana Basin are provided.

Animals vary considerably in size, shape, and physiological features across individuals, but yet achieve remarkably similar behavioral performances. We examined how animals compensate for morphophysiological variation by measuring the system dynamics of individual knifefish (Eigenmannia virescens) in a refuge tracking task. Kinematic measurements of Eigenmannia were used to generate individualized estimates of each fish’s locomotor plant and controller, revealing substantial variability between fish. To test the impact of this variability on behavioral performance, these models were used to perform simulated ‘brain transplants’—computationally swapping controllers and plants between individuals. We found that simulated closed-loop performance was robust to mismatch between plant and controller. This suggests that animals rely on feedback rather than precisely tuned neural controllers to compensate for morphophysiological variability., eLife digest People come in different shapes and sizes, but most will perform similarly well if asked to complete a task requiring fine manual dexterity – such as holding a pen or picking up a single grape. How can different individuals, with different sized hands and muscles, produce such similar movements? One explanation is that an individual’s brain and nervous system become precisely tuned to mechanics of the body’s muscles and skeleton. An alternative explanation is that brain and nervous system use a more “robust” control policy that can compensate for differences in the body by relying on feedback from the senses to guide the movements. To distinguish between these two explanations, Uyanik et al. turned to weakly electric freshwater fish known as glass knifefish. These fish seek refuge within root systems, reed grass and among other objects in the water. They swim backwards and forwards to stay hidden despite constantly changing currents. Each fish shuttles back and forth by moving a long ribbon-like fin on the underside of its body. Uyanik et al. measured the movements of the ribbon fin under controlled conditions in the laboratory, and then used the data to create computer models of the brain and body of each fish. The models of each fish’s brain and body were quite different. To study how the brain interacts with the body, Uyanik et al. then conducted experiments reminiscent of those described in the story of Frankenstein and transplanted the brain from each computer model into the body of different model fish. These “brain swaps” had almost no effect on the model’s simulated swimming behavior. Instead, these “Frankenfish” used sensory feedback to compensate for any mismatch between their brain and body. This suggests that, for some behaviors, an animal’s brain does not need to be precisely tuned to the specific characteristics of its body. Instead, robust control of movement relies on many seemingly redundant systems that provide sensory feedback. This has implications for the field of robotics. It further suggests that when designing robots, engineers should prioritize enabling the robots to use sensory feedback to cope with unexpected events, a well-known idea in control engineering.

Eigenmannia is one of the more taxonomically complex genera within the Gymnotiformes. Here we adopt an integrative taxonomic approach, combining osteology, COI gene sequences, and geometric morphometrics to describe three new species belonging to the E. trilineata species group from Colombian trans-Andean region. These new species increase the number of species in the E. trilineata complex to 18 and the number of species in the genus to 25. The distribution range of the E. trilineata species group is expanded to include parts of northwestern South America and southern Central America. RESUMEN Eigenmannia es uno de los géneros taxonómicamente más complejos dentro de los Gymnotiformes. En este artículo adoptamos un enfoque taxonómico integrador, que combina osteología, secuencias del gene COI y morfometría geométrica, para describir tres nuevas especies que pertenecen al grupo de especies de E. trilineata de la región transandina de Colombia. Estas nuevas especies aumentan el número de especies en el complejo E. trilineata a 18 y el número de especies en el género a 25. El rango de distribución del grupo de especies de E. trilineata se ha expandido al noroeste de Sudamérica y el sur de América Central.

Field studies on freely behaving animals commonly require tagging and often are focused on single species. Weakly electric fish generate a species- and individual-specific electric organ discharge (EOD) and therefore provide a unique opportunity for individual tracking without tagging. We here present and test tracking algorithms based on recordings with submerged electrode arrays. Harmonic structures extracted from power spectra provide fish identity. Localization of fish based on weighted averages of their EOD amplitudes is found to be more robust than fitting a dipole model. We apply these techniques to monitor a community of three species,Apteronotus rostratus,Eigenmannia humboldtii, andSternopygus dariensis, in their natural habitat in Darién, Panamá. We found consistent upstream movements after sunset followed by downstream movements in the second half of the night. Extrapolations of these movements and estimates of fish density obtained from additional transect data suggest that some fish cover at least several hundreds of meters of the stream per night. Most fish, includingEigenmannia, were traversing the electrode array solitarily. Fromin-situmeasurements of the decay of the EOD amplitude with distance of individual animals we estimated that fish can detect conspecifics at distances of up to 2 m. Our recordings also emphasize the complexity of natural electrosensory scenes resulting from the interactions of the EODs of different species. Electrode arrays thus provide an unprecedented window into the so-far hidden nocturnal activities of multispecies communities of weakly electric fish at an unmatched level of detail.Summary statementDetailed movement patterns and complex electrosensory scenes of three species of weakly electric fish were tracked without tagging using a submerged electrode array in a small Neotropical stream.

A new species of Eigenmannia is described from the Rio Pucuro, Rio Tuira basin, Panama. It is diagnosed from all congeners by the position of the mouth, the color pattern, the number of anal-fin rays, the number of scales on lateral line, the number of scales rows above the lateral line, the number and arrangement of teeth on the dentary, the number of precaudal vertebrae, the relative depth of the posterodorsal expansion on infraorbitals 1+2, and the relative size of coronomeckelian bone. The new species is the first Eigenmannia described from Central American drainages, and the northernmost species of the genus. Una nueva especie de Eigenmannia es descrita del rio Pucuro, que pertenece a la cuenca del Rio Tuira, Panama. Esta diagnosticada de las demas especies del genero por la posicion de la boca, el padron de coloracion, el numero de radios de la aleta anal, el numero de escamas de la linea lateral, el numero de hileras de escamas arriba de la linea lateral, el numero y disposicion de los dientes en e...

We report four mitochondrial genomes of South American electric knifefishes, derived from target capture and Illumina sequencing (HiSeq 2500 PE100). Two trans-Andean species Eigenmannia humboldtii (mitochondrial consensus genome of 25 individuals) and Sternopygus aequilabiatus (mitochondrial consensus genome of 30 individuals) from Colombia and two cis-Andean species Eigenmannia limbata from Suriname and Sternopygus macrurus from Argentina. Regarding Eigenmannia humboldtii, Eigenmannia limbata, and Sternopygus macrurus mitochondrial genomes have 13 protein-coding genes, 1 D-loop, 2 ribosomal RNAs, 22 transfer RNAs, and are 13,394 bp, 10,921 bp, and 13,013 bp in length respectively, for Sternopygus aequilabiatus mitochondrial genomes have 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and is 14,270 bp in length.

Neuromorphic photonics use light to imitate the neural models and systems of nature for solving complex human problems that are challenging for conventional electronic approaches. Neural algorithms are natural designs that govern the survival of the organism, therefore, are highly effective for the designated tasks. In this paper, we review two small-scale neural algorithms – spike timing dependent plasticity process for learning and jamming avoidance response in Eigenmannia, discuss the marriage of those neural algorithm and photonics, as well as explore their real-life applications in human society.

Glass knifefish (Eigenmannia) are a group of weakly electric fishes found throughout the Amazon basin. Their electric organ discharges (EODs) are energetically costly adaptations used in social communication and for localizing conspecifics and other objects including prey at night and in turbid water. Interestingly, a troglobitic population of blind cavefish Eigenmannia vicentespelea survives in complete darkness in a cave system in central Brazil. We examined the effects of troglobitic conditions, which includes a complete loss of visual cues and potentially reduced food sources, by comparing the behavior and movement of freely behaving cavefish to a nearby epigean (surface) population (Eigenmannia trilineata). We found that the strengths of electric discharges in cavefish were greater than in surface fish, which may result from increased reliance on electrosensory perception, larger size, and sufficient food resources. Surface fish were recorded while feeding at night and did not show evidence of territoriality, whereas cavefish appeared to maintain territories. Surprisingly, we routinely found both surface and cavefish with sustained differences in EOD frequencies that were below 10 Hz despite being within close proximity of about 50 cm. A half century of analysis of electrosocial interactions in laboratory tanks suggest that these small differences in EOD frequencies should have triggered the “jamming avoidance response,” a behavior in which fish change their EOD frequencies to increase the difference between individuals. Pairs of fish also showed significant interactions between EOD frequencies and relative movements at large distances, over 1.5 m, and at high differences in frequencies, often >50 Hz. These interactions are likely “envelope” responses in which fish alter their EOD frequency in relation to higher order features, specifically changes in the depth of modulation, of electrosocial signals.

A new species of Eigenmannia is described from the rio Mutum, tributary of upper rio Juruena, rio Tapajós basin, Comodoro, Mato Grosso, Brazil. The new species is distinguished from all congeners by coloration pattern, position of the mouth, number of scales rows above lateral line, number of premaxillary and dentary teeth, number of precaudal vertebrae, orbital diameter, mouth width, relative depth of posterodorsal expansion on infraorbitals 1+2 and relative size of coronomeckelian bone. Comments on potentially useful characters in phylogenetic studies derived from musculature, discussion on Eigenmannia species-group and the first dichotomous key for Eigenmannia are provided.

Made available in DSpace on 2018-12-11T16:40:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-01 This study provides the most comprehensive Model-Based Total Evidence (MBTE) phylogenetic analyses of the clade Gymnotiformes to date, reappraising relationships using a dataset comprised of six genes (5277 bp) and 223 morphological characters, and an ingroup taxon sample including 120 of 212 valid species representing 34 of the 35 extant genera. Our MBTE analyses indicate the two main gymnotiform clades are Gymnotidae and Sternopygoidei, the latter comprised of Rhamphichthyoidea (Rhamphichthyidae + Hypopomidae) and Sinusoidea (Sternopygidae + Apteronotidae). Within Gymnotidae, Electrophorus and Gymnotus are sister taxa, and Gymnotus includes the following six clades: (i) G. pantherinus clade, (ii) G. coatesi clade, (iii) G. anguillaris clade, (iv) G. tigre clade, (v) G. cylindricus clade, and (vi) G. carapo clade. Within Rhamphichthyoidea, Steatogenae (Steatogenys + Hypopygus) is a member of Rhamphichthyidae, and Hypopomidae includes the following clades: (i) Akawaio, (ii) Hypopomus, (iii) Microsternarchini, and (iv) Brachyhypopomus. Within Sternopygidae, Sternopygus and Eigenmanninae are sister groups, Rhabdolichops is the sister to other Eigenmanninae, Archolaemus+. Distocyclus is the sister to Eigenmannia, and Japigny is nested within Eigenmannia. Within Apteronotidae, Sternarchorhamphinae (Sternarchorhamphus + Orthosternarchus) is the sister to Apteronotinae, Adontosternarchus is the sister group to other Apteronotinae, Sternarchorhynchini (Sternarchorhynchus + Platyurosternarchus) is the sister to Navajini, and species assigned to Apteronotus are members of two separate clades: (i) A. sensu stricto in the Apteronotini, and (ii) the A. bonapartii clade in the Navajini. Universidade Estadual Paulista - UNESP Instituto de Biociências de Botucatu University of Louisiana at Lafayette Department of Biology Universidade Estadual Paulista - UNESP Instituto de Biociências de Botucatu

Eigenmannia oradens, new species Figs. 1��� 3, Table 1 Holotype. ANSP 190768, xr, 121.6 mm LEA, Venezuela, Amazonas, R��o Ventuari at Raudales Chipirito, 88.5 Km east of San Fernando de Atabapo, 04��04���6���N 66��54���13���W, 0 1 April 2010, M. Sabaj-P��rez, N.K. Lujan, D.C. Werneke, T. Carvalho, S. Meza V., A. Luna & O. Santaella. Paratypes. ANSP 190912, 2 xr, 62.6���101.1 mm LEA, Venezuela, Amazonas, R��o Ventuari ca. 20 airmiles NE of confluence with R��o Orinoco, near ornamental fish market in river, 04��04���32���N 66��53���34���W, 0 3 April 2005, N.K. Lujan, M. Arce, E.L. Richmond, M.P. Grant & T.E. Wesley. ANSP 203212, 1xr, 76.7 mm LEA, collected with the holotype, MPEG 35287, 1xr+1CS, 94.7���111.1 mm LEA, collected with the holotype. MZUSP 122802, 1MS, 102.3 mm LEA, collected with the holotype. USNM 440377, 1xr, 91.4 mm LEA, collected with the holotype. Diagnosis. Eigenmannia oradens differs from all congeners by presence of bony dorsolateral flange of dentary which also anchors numerous teeth along its extension (versus dorsolateral flange absent and teeth are attached only in dentary rim), and first premaxillary teeth row mobile, teeth attached to anteroventral margin of premaxilla (versus first premaxillary teeth row immobile, teeth completely attached to ventral surface of premaxilla). It is further distinguished from remain congeners, except E. besouro Peixoto & Wosiacki, 2016, E. correntes Camposda-Paz & Queiroz, 2017, E. meeki Dutra, de Santana & Wosiacki, 2017, E. vicentespelaea Triques, 1996, E. virescens Valenciennes, 1836, and E. waiwai Peixoto, Dutra & Wosiacki, 2015 by the subterminal mouth (versus terminal: Fig. 2). The new species is diagnosed from E. besouro, E. correntes, E. meeki, E. vicentespelaea, and E. virescens by having 38���42 teeth on premaxilla (versus 18���29 in E. besouro, 17���20 in E. correntes, 30���35 in E. meeki, 25���26 in E. vicentespelaea, and 22 in E. virescens). It is distinguished from E. besouro, E. correntes, E. meeki, E. virescens, and E. waiwai by the coronomeckelian bone corresponding to 45% of length of Meckel���s cartilage (versus 20% of length of Meckel���s cartilage in E. correntes, E. meeki, E. virescens and E. waiwai and 30% of length of Meckel���s cartilage in E. besouro). Eigenmannia oradens also differs from E. meeki, E. vicentespelaea, and E. waiwai by having 99���107 scales along lateral line until the end of anal fin (versus 140���168 in E. meeki, 110���125 in E. vicentespelaea, and 111���128 in E. waiwai). It is further distinguished from E. besouro, E. correntes, E. vicentespelaea and E. waiwai by absence of superior midlateral stripe (versus presence). The new species is additionally diagnosed from E. meeki, E. virescens, and E. waiwai by depth of posterodorsal expansion on infraorbitals 1+2 approximately equal to total length of infraorbitals 1+2 (versus less than 50% of the length of infraorbitals 1+2). Eigenmannia oradens also differs from E. besouro, E. correntes and E. waiwai by having ii, 16���17 pectoral fin rays (versus ii, 13���14 in E. besouro, ii, 11���12 in E. correntes, and ii, 13���15 in E. waiwai). It is distinguished from E. correntes and E. meeki by having 31���38 dentary teeth (versus 16���18 and 20���23 respectively), and 164���192 anal-fin rays (versus 211���240). It also differs from E. virescens by presence of narrow stripe on lateral line (versus absence). Eigenmannia oradens is diagnosed from E. waiwai by having 14 precaudal vertebrae (versus 12 or 13). Description. Body shape and pigmentation in Figs. 1 and 2. Morphometric data for examined specimens in Table 1. Largest examined specimen 121.6 mm LEA. Body elongate, distinctly compressed laterally. Greatest body depth at vertical through distal margin of pectoral fin. Dorsal profile of body convex to straight. Ventral profile slightly convex. Caudal filament elongate. Head compressed, greatest width in opercular region and greatest depth at nape (Fig. 2). Dorsal profile of head convex. Ventral profile of head slightly straight. Snout subconical in lateral view. Mouth subterminal. Premaxillary teeth 38(1) or 42 (1) arranged in five (1) or six (1) rows. First premaxillary teeth row mobile, teeth attached only to anteroventral margin of premaxilla. Maxilla slender with short, hook-shaped anterodorsal process. Posterior margin of maxilla reaching posterior margins of first and second infraorbitals. Dentary teeth 31(1) or 38(1) arranged in three (2) rows. Dentary teeth attached in bony dorsolateral flange of dentary (Fig. 3). Coronomeckelian bone corresponds to 45% of length of Meckel���s cartilage. Endopterygoid teeth 10(1) arranged in single row. Mouth rictus extending posteriorly to vertical between nares or on posterior nostril. Anterior naris tube-like, closer to snout tip than to anterior margin of eye. Posterior naris rounded, without tube; near midpoint between anterior naris and anterior margin of eye. Eye small, circular, completely covered by thin membrane, on anterior one-half of HL and laterally oriented. Antorbital and infraorbitals 1 to 4 enlarged, partially cylindrical with slender osseous arches. Fifth and sixth infraorbitals slender and tubular. Depth of posterodorsal expansion on infraorbitals 1+2 equals total length of infraorbitals 1+2. Gill opening limited to posterior margin of opercle and extending above and below pectoral-fin base. Gill rakers tiny and fleshy. Seven (1) gill rakers on first ceratobranchial. Six (2) gill rakers on first infrapharyngobranchial. Upper pharyngeal plate with 10(1) teeth. Lower pharyngeal plate with nine (1) teeth. Branchial membranes joined at isthmus. Branchiostegal rays five (1). First and second branchiostegal rays narrow. Third to fifth branchiostegal rays spatulate. First to fourth branchiostegal rays attached to anterior ceratohyal. Fifth branchiostegal ray attached to posterior ceratohyal. Anus and urogenital papilla adjacent. Position of anus and urogenital papilla shifting through ontogeny from vertical through posterior margin of eye to vertical through middle of eye. Scales small, cycloid, extending from immediately posterior of head to tip of caudal filament. Scales present on mid-dorsal region of body. Scales above lateral line at midbody eight(4), nine(1), ten*(2), or 11(1). Lateral-line scales to vertical through anal-fin terminus 99(1), 100(3), 104(1), 105(2), or 107*(1). Pectoral-fin rays ii,16(7) or ii,17*(1). Three proximal radials. Distal pectoral-fin margin straight. Total anal-fin rays 164(1), 173(1), 177(1), 178*(2), 182(1), or 192(1). Anal-fin origin below pectoral-fin insertion. Distal margin of anal fin straight. First unbranched rays tiny; rays progressively increasing in size to first branched rays. Branched rays all of nearly equal length, except for posterior most rays that progressively decrease in size. Precaudal vertebrae 14*(7). Transitional vertebrae three (3) or four* (4). Vertebrae to end of anal fin 57(1), 59(2), 60(2) or 61(1). Pleural ribs six*(3) or seven (7). Displaced hemal spines four* (7). Coloration in alcohol. Body ground coloration cream. Body densely covered by dark chromatophores gradually more spaced ventrally. Chromatophores more concentrated on perforated scales forming lateral line stripe (Fig. 1). Second layer of pigmentation formed by multiple, small bars of dark chromatophores situated between musculature associated with anal-fin pterygiophores. Dark individual bars in combination form two stripes-like patterns. Inferior midlaterial stripe approximately as wide as orbital diameter. Anal-fin base stripe approximately as wide as orbital diameter. Head densely covered by dark chromatophores gradually more spaced ventrally. Lips distinctly darker than proximate areas. Pectoral and anal fins hyaline with scattered dark chromatophores overlying fin rays. Distribution. Eigenmannia oradens is only known from its type locality in the R��o Ventuari, R��o Orinoco basin, Estado Amazonas in Venezuela (Fig. 4). Etymology. The specific epithet, oradens, is from the Latin ora, meaning edge, and dens, meaning tooth, in allusion to the presence of a bony dorsolateral flange on the dentary in which teeth are attached. An adjective. Remarks. Eigenmannia oradens can be diagnosed among congeners by a remarkable arrangement of the oral dentition. In the premaxilla the anterobasal margin of the first tooth row is attached to it surface. Consequently, this arrangement, gives mobility freedom to the teeth, which can reach 90 degrees from the vertical. This type of attachment is also known in species of Archolaemus (Vari et al., 2012). Broadly, the premaxilla attachment in Archolaemus and E. oradens can be included in the Type 3 of Fink (1981) [���...a tooth attachment mode which acts as a hinge, with its axis of rotation being the anterior tooth attachment site���; pg. 176]. In contrast, the first tooth row is completely attached to the premaxilla in Sternopygidae, Type 2 of Fink (1981). The dentary of E. oradens is characterized by a bony dorsolateral flange, which anchors numerous teeth along its extension (Fig. 3). Such condition also occurs in Archolaemus, D. guchereauae, and Japigny. And according to the current hypotheses of phylogenetic relationships it is considered a convergence among the four taxa (e.g., Tagliacollo et al., 2016). As noted in the diagnosis for the new species, the number of teeth rows of premaxilla and dentary have a large variation across Eigenmannia and can be explored as source of taxonomic characters. The description of E. oradens corroborates with previous studies that used teeth arrangement and attachment as a valuable source of taxonomic information at different hierarchical levels (e.g., Vari et al., 2012; Peixoto et al., 2015; Peixoto & Wosiacki, 2016; Campos-da-Paz & Queiroz, 2017; Dutra et al., 2017; Peixoto & Waltz, 2017). Comparative material examined. Archolaemus blax: INPA 6424, 20+4CS, 118���270mm TL, Rio Tocantins above Tucuru�� Dam, Brazil. MNRJ 12158, 18+4CS of 93, 90.0���382.0 mm TL, Rio Bezerra, Rio Tocantins basin, Brazil. Archolaemus ferreirai: INPA 6422, 8+4CS paratypes, 131.0���269.0 mm TL, Rio Mucaja��, Rio Branco basin, Brazil. INPA 36379, 20+1CS paratype, 119.0���342.0 mm TL, Rio Mucaja��, Rio Branco basin, Brazil. Archolaemus janeae: INPA 36380, 14+2CS paratypes, 136.0���225.0 mm TL, Rio Iriri, Rio Xingu basin, Brazil. Archolaemus luciae: INPA 20964, 8+4CS paratypes, 106.0���200.0 mm TL, Rio Trombetas, Brazil. Archolaemus orientalis: FMNH 94418, 1CS of 3 paratype, Rio S��o Francisco, Brazil. MPEG 21508, holotype, 156.0 mm TL, Rio Paracatu, Rio S��o Francisco basin, Brazil. MPEG 21509, 1MS paratype, 150.0 mm TL, Rio Paracatu, Rio S��o Francisco basin, Brazil. Archolaemus santosi: INPA 36382, 6+3CS paratypes, 73.0���212.0 mm TL, Rio Jamari, Rio Madeira basin, Brazil. Distocyclus conirostris: INPA 11482, 7+3CS of 32, 100.2���197.0 mm LEA, Rio Purus, Brazil. INPA 28879, 2CS of 19, 108.7���165.0 mm LEA, Rio Negro, Brazil. INPA 28915, 2CS of 11, 108.1��� 130.5 mm LEA, Rio Negro, Brazil. INPA 34018, 8+1CS, 132.0��� 174.5 mm LEA, Praia Grande above community of Carapan��, Rio Purus basin, Brazil. MPEG 20023, 2+1CS, 120.9���196.4 mm LEA, Rio Arari, Ilha do Maraj��, Brazil. MPEG 20024, 2+1CS, 149.1���181.0 mm LEA, Rio Arari, Ilha do Maraj��, Brazil. MZUSP 6982, 2+1CS, 156.2���166.0 mm LEA, Rio Madeira, Brazil. Distocyclus guchereauae: MNHN 2003-0013, 1, 222.0 mm TL, Maroni drainage, French Guiana. MNHN 2003-0014, 1, 232.0 mm TL, Maroni drainage, French Guiana. MNHN 2003-0018, 2, 322.0���321.0 mm TL, Maroni drainage, French Guiana. Eigenmannia antonioi: MPEG 10182, 6+1CS paratypes, 77.0��� 118.3 mm LEA, Rio Anapu, Brazil. Eigenmannia besouro: MZUSP 57890, holotype, 91.9 mm LEA, Rio Grande, S��o Desid��rio, Brazil; MZUSP 119104, 5+1CS, paratypes, 69.6���106.1 mm LEA. MZUSP 83792, 6+1CS, paratypes, 55.8���68.8 mm LEA, Rio Preto, Brazil. Eigenmannia desantanai: NUP 3470, 10+1CS paratypes, 119.8��� 142.8 mm LEA, Rio Cuiab��, Brazil. Eigenmannia guairaca: NUP 6467, 8+2CS paratypes, 81.4���135.8 mm LEA, Riacho ��gua do ��, Brazil. Eigenmannia humboldtii: IAvH-P 6788, 1, 316.7 mm LEA, R��o Atrato, Colombia. IAvH-P 6794, 1, 330.0 mm LEA, R��o Atrato, Colombia. IAvH-P 6800, 288.3 mm LEA, R��o Atrato, Colombia. IAvH-P 6806, 1CS, 205.7 mm LEA, R��o Atrato, Colombia. IAvH-P 7024, 1, 199.8 mm LEA, R��o Atrato, Colombia. IAvH-P 7415, 2, 240.9��� 270.1 mm LEA, R��o Atrato, Colombia. IAvH-P 7822, 1, 312.0 mm LEA, R��o Magdalena, Colombia. IAvH-P 7823, 1, 264.0 mm LEA, R��o Magdalena, Colombia. NRM 27741, 1, 294.1 mm LEA, Can�� Ponelaolla, Colombia. USNM 247229, 3, 134.9��� 175.6 mm LEA, R��o Salado, Colombia. Eigenmannia limbata: INPA 18288, 2CS, 98.0���151.0 mm LEA, Lago Mamirau��, Brazil. USNM 305802, 10+2CS, 122.6���250.5 mm LEA, Rio Matos, Bolivia. Eigenmannia macrops: BMNH 1897.8.6.1, holotype, 128.5mm LEA, Potaro River, Guyana. USNM 402684, 6, 80.1���116.8 mm LEA, Cuyuni River, Guyana. USNM 405265, 3, 56.3���107.8 mm LEA, Cuyuni River, Guyana. USNM 405266, 15+1CS, 63.3���162.9 mm LEA, Cuyuni River, Guyana. Eigenmannia matintapereira: MZUSP 109618, 3+1CS paratypes, 79.7���143.6 mm LEA, Rio Uneiuxi, Brazil. MZUSP 109695, 5+1CS paratypes, 65.7���167.7 mm LEA, Rio Urubaxi, Brazil. Eigenmannia meeki: USNM 293171, holotype, 235.7 mm LEA, R��o Pucuro, Panam��. MPEG 33912, 1+1 CS, 194.6���222.0 mm LEA, R��o Pucuro, Panam��. Eigenmannia microstoma: BMNH 1868.7.8.2���3, 2 syntypes, 101.1���139.3 mm LEA, Rio S��o Francisco basin, Brazil. ZMUC P2516 (formally ZMUC 21), 1 syntype (photo and radiograph), 162.8 mm LEA, Rio S��o Francisco basin, Brazil. ZMUC P2517 (formally ZMUC 23), 1 syntype, 153.8 mm LEA, Rio S��o Francisco basin, Brazil. ZMUC P2518 (formally ZMUC 24), 1 syntype, 176.6 mm LEA, Rio S��o Francisco basin, Brazil. ZMUC P2519 (formally ZMUC 25), 1 syntype, 105.1 mm LEA, Rio S��o Francisco basin, Brazil. ZMUC P2520 (formally ZMUC 26), 1 syntype, 101.1 mm LEA, Rio S��o Francisco basin, Brazil. MCP 45216, 5+1CS, 57.7���91.6 mm LEA, Rio Pandeiros, Brazil. Eigenmannia muirapinima: MPEG 21777, 1+3CS paratypes, 84.6���98.5 mm LEA, Lago Jar��, Brazil. MPEG 29489, 11+2CS paratypes, 76.2���97.7 mm LEA, Igarap�� Santo Ant��nio, Brazil. Eigenmannia nigra: ANSP 162130, 3 paratypes, 243.0���265.0 mm LEA, R��o Casiquiare, Venezuela. BMNH 1998.3.17, 8 of 15, 133.0��� 192.9 mm LEA, Paran�� Apara, Brazil. CAS 54387, 3+1CS of 5, 139.2��� 166.9 mm LEA, R��o Orinoco bifurcation, Venezuela. CAS 54518, 1, 130.3 mm LEA, R��o Orinoco bifurcation, Venezuela. INPA 9976, 3+1CS of 10, 149.7��� 223.1 mm LEA, Paran�� Apara, Brazil. INPA 15813, 12, 148.4��� 222.4 mm LEA, Lago Tef��, Brazil. USNM 260240, 4+1CS of 22, 192.2��� 225.2 mm LEA, main channel of R��o Apure, Venezuela. Eigenmannia pavulagem: MPEG 9524, 3CS paratypes, 90.7���108.5 mm LEA, Igarap�� Anuera-Grande, Brazil. MPEG 29490 paratypes, 25+2CS, 26.2���176.6 mm LEA, Igarap�� Paraquequara, Brazil. Eigenmannia sayona: MZUSP 96497, holotype, 131.8 mm LEA, R��o Parguaza, Cede��o, Venezuela; MZUSP 119711, paratypes, 6+2CS, 27.8-116.2 mm LEA. Eigenmannia trilineata: UFRGS 6635, 10, 58.5���143.8 mm LEA, Rio Tramanda��, Brazil. UFRGS 6790, 12, 92.8���159.1 mm LEA, Arroio Gueromana, Brazil. UFRGS 8788, 3, 114.2��� 130.5 mm LEA, Rio Pardo, Brazil. UFRGS 13329, 1, 124.3 mm LEA, Arroio Corrientes, Brazil. Eigenmannia virescens: MCP 12474, 1, 190.1 mm LEA, Rio Uruguai, Brazil. MCP 13416, 5, 148.7���196.0, Rio do Peixe, Brazil. MCP 16797, 5+2CS, 143.7���182.0 mm LEA, Rio Ijuizinho, Brazil. MCP 19330, 1, 147.0 mm LEA, Rio Uruguai, Brazil. MCP 21139, 3, 157.3��� 236.1 mm LEA, Rio das Antas, Brazil. MCP 26819, 1, 212.9 mm LEA, Rio Ibicui, Brazil. Eigenmannia vicentespelaea: MZUSP 83461, 3+1CS, 108.0��� 164.5 mm LEA, Cave of S��o Vicente I, Brazil. Eigenmannia waiwai, INPA 37594, 31+2CS paratypes, 94.0��� 138.1 mm LEA, Rio Mapuera, Brazil. INPA 37567, 3+1CS paratypes, 74.9���154.8 mm LEA, Cachoeira Porteira, Brazil. ��� Eigenmannia ��� goajira: USNM 121596, holotype, 377.0 mm LEA, R��o Socuy, Venezuela. USNM 121596, 1, paratype, 335.6 mm LEA, R��o Socuy, Venezuela. Japigny kirschbaum: MNHN 2008-1201, 110.9 mm TL, holotype, Mana River, French Guiana; MNHN 2000-5954, 2, 99���111 mm TL, paratypes, Maroni drainage, French Guiana. FMNH 50185, 3CS, New River drainage, head of Itabu Creek, Guyana. Rhabdolichops caviceps: INPA 20157, 8+2CS, 108.7���134.5 mm LEA, Paran�� do Xiboquena, tributary of Rio Solim��es, Brazil. Rhabdolichops eastwardi: INPA 12361, 2CS of 41, Lago do Prato, Rio Negro, Amazonas, Brazil. MPEG 1189, 2CS, 115.1���127.8 mm LEA, Rio Goiapi, Ilha do Maraj��, Brazil. Rhabdolichops electrogrammus: INPA 28863, 8+2CS of 79, 96.8��� 101.5 mm LEA, Rio Negro, Brazil. Rhabdolichops lundbergi: INPA 11406, 7+3CS of 111, 133.6��� 155.6 mm LEA, Rio Coari, tributary of Rio Solim��es, Brazil. Rhabdolichops nigrimans: INPA 28862, 11+2CS, 97.3���132.0 mm LEA, Rio Negro, Brazil. Rhabdolichops troscheli: MPEG 1174, 1, Rio Goiapi, Ilha do Maraj��, Brazil. MPEG 2604, 9+2CS, 90.0��� 94.7 mm LEA, Rio Goiapi, Ilha do Maraj��, Brazil. MPEG 2803, 1CS, 222.0 mm LEA, Rio Goiapi, Ilha do Maraj��, Brazil. MPEG 8482, 1CS, 170.1 mm LEA, Tom��-A��u, Par��, Brazil., Published as part of Dutra, Guilherme Moreira, Peixoto, Luiz Ant��nio Wanderley, Santana, Carlos David De & Wosiacki, Wolmar Benjamin, 2018, A new species of Eigenmannia Jordan & Evermann (Teleostei: Gymnotiformes: Sternopygidae) from R��o Ventuari, Venezuela, pp. 132-140 in Zootaxa 4422 (1) on pages 133-138, DOI: 10.11646/zootaxa.4422.1.8, http://zenodo.org/record/1251065, {"references":["Peixoto, L. A. W. & Wosiacki, W. B. (2016) Eigenmannia besouro, a new species of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae) from the rio Sao Francisco basin, northeastern Brazil. Zootaxa, 4126 (2), 262 - 270. https: // doi. org / 10.11646 / zootaxa. 4126.2.6","Campos-da-Paz, R. & Queiroz, I. R. (2017) A new species of Eigenmannia Jordan and Evermann (Gymnotiformes: Sternopygidae) from the upper rio Paraguai basin. Zootaxa, 4216, 73 - 84. https: // doi. org / 10.11646 / zootaxa. 4216.1.5","Dutra, G. M., de Santana, C. D. & Wosiacki, W. B. (2017) A new species of the glass electric knifefish genus Eigenmannia Jordan and Evermann (Teleostei: Gymnotiformes: Sternopygidae) from Rio Tuira Basin, Panama. Copeia, 105, 85 - 91. https: // doi. org / 10.1643 / CI- 16 - 439","Peixoto, L. A. W., Dutra, G. M. & Wosiacki, W. B. (2015) The Electric Glass Knifefishes from the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zoological Journal of the Linnean Society, 175, 384 - 414. https: // doi. org / 10.1111 / zoj. 12274","Vari, R. P., de Santana, C. D. & Wosiacki, W. B. (2012) South American eletric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society, 165, 670 - 699. https: // doi. org / 10.1111 / j. 1096 - 3642.2012.00827. x","Fink, W. L. (1981) Ontogeny and phylogeny of tooth attachment modes in Actinopterygian Fishes. Journal of Morphology, 167, 167 - 184. https: // doi. org / 10.1002 / jmor. 1051670203","Peixoto, L. A. W & Waltz, B. T. (2017) A new species of the Eigenmannia trilineata species group from the Rio Orinoco basin, Venezuela (Gymnotiformes: Sternopygidae). Neotropical Ichthyology, 15, e 150199. https: // doi. org / 10.1590 / 1982 - 0224 - 20150199"]}

Eigenmannia 1. Two inconspicuous dark-brown longitudinal stripes on the flank.............................................................. E. virescens 1’. Three or four conspicuous dark-brown longitudinal stripes on the flank.............................................................. 2 2. Premaxilla with nine or 10 teeth distributed in two rows; pectoral fin with ii,11 or 12 rays and anal fin with 151 to 170 rays.............................................................. E. guairaca 2’. Premaxilla with 31 to 33 teeth distributed in four rows; pectoral fin with ii,14 or 15 rays and anal fin with 176 to 217 rays.............................................................. E. trilineata, Published as part of Ota, Renata Rúbia, Deprá, Gabriel de Carvalho, Graça, Weferson Júnio da & Pavanelli, Carla Simone, 2018, Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated, pp. 1-111 in Neotropical Ichthyology 16 (2) on page 59, DOI: 10.1590/1982-0224-20170094, http://zenodo.org/record/3678395

Eigenmannia guairaca Peixoto, Dutra, Wosiacki, 2015 Fig. 17 Body elongated and compressed; greatest body depth contained 5.9 to 7.0 times in TL; head length 6.5 to 8.3, anal-fin base length 0.7 to 1.2, caudal filament length 2.8 to 4.5, preanal distance 5.0 to 6.0 and prepectoral distance 6.1 to 7.7 in LEA; snout length 3.8 to 4.9, horizontal orbital diameter 6.7 to 8.8 and least interorbital width 2.7 to 3.5 in HL. Mouth terminal; premaxilla with 9 or 10 teeth distributed in two rows. Pectoral fin with 12 or 13 rays and anal fin with 151-170 rays. Lateral line complete, with 110- 143 pored scales; transverse series above lateral line with 9-11 scale rows. Ground color pale brown; four dark-brown longitudinal stripes on flank (one superior medial, one lateral line, one inferior medial and one at anal-fin base). Maximum total length. 173.0 mm TL. Distribution. Tributaries of the rio Iguatemi, and riacho Água do Ó, tributary of rio Paranapanema, upper rio Paraná basin. Remarks. Peixoto et al. (2015) reviewed the Eigenmannia trilineata species-group, described the new species, E. guaiaraca, from the riacho Água do Ó, tributary of the rio Paranapanema, upper rio Paraná basin, and restricted the distribution of E. trilineata to the lower rio Paraná basin. Analyzing additional material hosted at Coleção Ictiológica do Nupélia, specimens similar to E. guairaca were found in tributaries of the rio Iguatemi, right bank of the upper rio Paraná, and specimens similar to those redescribed as E. trilineata by Peixoto et al. (2015) in the upper rio Paraná floodplain and some of its tributaries (e.g. rio Paracaí). Therefore, the occurrence of both species in the studied region has been recorded., Published as part of Ota, Renata Rúbia, Deprá, Gabriel de Carvalho, Graça, Weferson Júnio da & Pavanelli, Carla Simone, 2018, Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated, pp. 1-111 in Neotropical Ichthyology 16 (2) on page 59, DOI: 10.1590/1982-0224-20170094, http://zenodo.org/record/3678395, {"references":["Peixoto LAW, Dutra GM, Wosiacki WB. The electric glass knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zool J Linn Soc. 2015; 175 (2): 384 - 414."]}