Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator

Is there only one electric eel species? For two and a half centuries since its description by Linnaeus, Electrophorus electricus has captivated humankind by its capacity to generate strong electric discharges. Despite the importance of Electrophorus in multiple fields of science, the possibility of additional species-level diversity in the genus, which could also reveal a hidden variety of substances and bioelectrogenic functions, has hitherto not been explored. Here, based on overwhelming patterns of genetic, morphological, and ecological data, we reject the hypothesis of a single species broadly distributed throughout Greater Amazonia. Our analyses readily identify three major lineages that diverged during the Miocene and Pliocene—two of which warrant recognition as new species. For one of the new species, we recorded a discharge of 860 V, well above 650 V previously cited for Electrophorus, making it the strongest living bioelectricity generator. © 2019, The Author(s)

Sistemática de Trichomycteridae (Ostariophysisiluriformes) na Bacia do Rio Iguaçu a montante das cataratas, com a descrição de oito espécies novas

Orientador: Prof. Dr. Júlio César GaravelloDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Curso de Pós-Graduação em Ciências Biológicas - ZoologiaInclui referências: p. 108-114Área de concentração: ZoologiaResumo: Sistemática de Trichomycteridae (Ostariophysi - Siluriformes) na Bacia do Rio Iguaçu, a montante das Cataratas, com a descrição de oito espécies novas. Trichomycteridae é uma família de peixes de pequeno porte, comumente referidos como "parasitas" e conhecidos como "candirus". Atualmente são conhecidos cerca de 25 gêneros nominais, com cerca de 200 espécies descritas. A Bacia do Iguaçu (25° S e 26° 40’S e 49° W e 54° e 35° 35’ W), drena 72.000 km² e apresenta uma ictiofauna com elevado grau de endemismo, estudada por diversos pesquisadores que têm registrado e descrito novas espécies. O presente trabalho tem por objetivo elaborar um inventário dos Trichomycteridae da Bacia do Rio Iguaçu, a montante das Cataratas, redescrevendo espécies antigas e apresentando novas espécies. São analisados exemplares da Bacia do Iguaçu e bacias limítrofes (Rio Ribeira, Rio Paraná, Rio Tibagi, Rio Uruguai, Rio Cubatão e das Laranjeiras) e do Rio Paraíba do Sul. Dois gêneros e 20 espécies foram identificadas entre 348 indivíduos estudados. Registrou-se a ocorrência de onze espécies do gênero Trichomycterus na Bacia do Iguaçu a montante das cataratas, das quais oito são aqui descritas como novas. T. davisi e T. stawiarski são redescritas com base em material tipo e exemplares adicionais. Para T. castroi, são adicionadas à descrição original, diagnoses morfométricas e osteológicas, bem como uma descrição osteológica. É constatado que T. davisi não é endêmico da Bacia do Iguaçu, sendo confirmada sua ocorrência também nas nascentes do Rio Ribeira. Hipóteses de autapomorfias e sinapomorfias são apresentadas e discutidas. A distribuição de Trichomycterinae é discutida e prováveis novos registros na Bacia do Iguaçu são comentados. Uma chave dicotômica para as espécies de Trichomycterus da Bacia do rio Iguaçu a montante das cataratas é apresentada.Abstract: Systematics of Trichomycteridae (Ostariophysi - Siluriformes) on Iguaçu River Basin, above the Waterfalls, with the description of eight new species. Trichomycteridae is a family of little fishes, usually referred to as "parasitic" and known as "candirus". Nearly 25 nominal genera are known, with about 200 described species. The Iguaçu Basin (25°S and 26° 40’ S and 49° W and 54° W and 35° 35’W) drains 72.000 km² and has an ichthyiofauna with a high degree of endemism. Studies from several researchers have presented several new species. The present paper present an inventory of Trichomycteridae from Iguaçu Basin, above the Waterfalls, redescribing known species and describing new species. Specimens from the Iguaçu Basin, neighbouring basins ( Rio Ribeira, Rio Paraná, Rio Tibagi, Rio Uruguai, Rio Cubatão and das Laranjeiras) and of Rio Paraíba do Sul are analyzed. Two genera and 20 species were identified, among 348 specimens studied. Eleven species from the genus Trichomycterus were identified, among those eight are described as new. T. davisi and T. stawiarski are redescribed based on the type material and additional specimens. To T. castroi, added to the original description, morfometric and osteological diagnoses as well as an osteological description are presented. T. davisi isn’t endemic of Iguaçu Basin, and is also present in the upper reaches of the Rio Ribeira. Hypotheses of autapomorfic and sinapomorfic caracters are proposed. The distribution of Trichomycterinae is discussed and probable new records on Iguaçu Basin are commented. A key to species of Trichomycterus of Iguaçu Basin is presented

A new species of the neotropical catfish genus Trichomycterus (Siluriformes : Trichomycteridae) representing a new body shape for the family

Trichomycterus crassicaudatus is described as a new species from the Rio Iguacu basin in southern Brazil. The new species has an exceptionally deep posterior region of the body (caudal peduncle depth 22.8-25.4% SL), resulting in an overall shape which distinguishes it at once from all other members of the Trichomycteridae. The caudal fin of the species is broad-based and forked, a shape also distinguishing it from all other species in the family. A number of autapomorphic modifications of T. crassicaudatus are associated with the deepening of the caudal region, including an elongation of the hemal and neural spines of the vertebrae at the middle of the caudal peduncle. Phylogenetic relationships of the new species are yet unresolved, but it shares a similar color pattern and a thickening of caudal-fin procurrent rays with T. stawiarski, a poorly-known species also from the Rio Iguacu basin. Coloration and body shape also include similarities with T. lewi from Venezuela

Trichomycterus igobi, a new catfish species from the rio Iguaçu drainage: the largest head in Trichomycteridae (Siluriformes: Trichomycteridae).

Submitted by Francileila Silva ([email protected]) on 2010-10-17T01:14:42Z No. of bitstreams: 1 Neotropical Ichthyology v6 n1 2008 WOSIACKI.pdf: 392895 bytes, checksum: b61cbdd6d4dc964e40498ee599a932fd (MD5)Approved for entry into archive by Francileila Silva([email protected]) on 2010-10-17T01:15:32Z (GMT) No. of bitstreams: 1 Neotropical Ichthyology v6 n1 2008 WOSIACKI.pdf: 392895 bytes, checksum: b61cbdd6d4dc964e40498ee599a932fd (MD5)Made available in DSpace on 2010-10-17T01:15:32Z (GMT). No. of bitstreams: 1 Neotropical Ichthyology v6 n1 2008 WOSIACKI.pdf: 392895 bytes, checksum: b61cbdd6d4dc964e40498ee599a932fd (MD5) Previous issue date: 2008A new species of Trichomycterus is described for the rio Iguaçu drainage in Southern Brazil. Trichomycterus igobi, new species, is readily distinguishable from all other species currently in the genus by its extremely large head (23.8-26.8 % SL), which is proportionally the largest head in any Trichomycteridae. That characteristic plus the relatively deep body result in a very short-bodied overall aspect, the most extremely such case in the genus Trichomycterus. Other diagnostic features that distinguish the new species from most or all of its congeners include a short caudal peduncle (15.4-19.7 % SL); an almost entirely cartilaginous second hypobranchial (with only vestigial ossification); a mesial expanded palatine ossification; a narrow cleithrum, falciform in shape; and the lack of a proximal posterior concavity on the third ceratobranchial. The new species seems to form a monophyletic group with T. stawiarski and other undescribed species (T. sp. C), also endemic to the rio Iguaçu. As putative synapomorphies, the three species share a rigid spine-like morphology of individual procurrent caudalfin rays, an extended area of dorsal caudal-fin procurrent rays, and numerous branchiostegal rays (ten or eleven)

A new species of the neotropical catfish genus Trichomycterus (Siluriformes : Trichomycteridae) representing a new body shape for the family

Trichomycterus crassicaudatus is described as a new species from the Rio Iguacu basin in southern Brazil. The new species has an exceptionally deep posterior region of the body (caudal peduncle depth 22.8-25.4% SL), resulting in an overall shape which distinguishes it at once from all other members of the Trichomycteridae. The caudal fin of the species is broad-based and forked, a shape also distinguishing it from all other species in the family. A number of autapomorphic modifications of T. crassicaudatus are associated with the deepening of the caudal region, including an elongation of the hemal and neural spines of the vertebrae at the middle of the caudal peduncle. Phylogenetic relationships of the new species are yet unresolved, but it shares a similar color pattern and a thickening of caudal-fin procurrent rays with T. stawiarski, a poorly-known species also from the Rio Iguacu basin. Coloration and body shape also include similarities with T. lewi from Venezuela

A new species of leaffish Polycentrus Müller & Troschel, 1849 (Percomorpha: Polycentridae) from the rio Negro, Brazil

A new species of Polycentrusis described from the rio Negro, in Brazil. It is distinguished from P. schomburgkii by the presence of two dark postocular and one subocular band, all smaller than orbital diameter, blunt snout, isognathous mouth, reduction of the serrations on the lower edge of the lacrimal-spines ranging from zero to two tiny spines at the posterior end, intensely serrated edge of the interopercle, fully serrated posterior edge of the vertical arm of the preopercle, presence of five pungent opercular spines, subopercle broadly serrated along most of its posterior ventral edge, presence of serrations dorsally on the posterior margin of the cleithrum, fourth ray of pectoral fin reaching the vertical through the anal-fin origin, 19-21 predorsal scales, 19-20 scales on dorsal-fin base, 12-14 scales on anal-fin base, and absence of a median opercular blotch

Anew species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae) from the Tapajós basin, Brazil

Castro, Íthalo Da Silva, Wosiacki, Wolmar Benjamin (2019): Anew species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae) from the Tapajós basin, Brazil. Zootaxa 4701 (5): 461-472, DOI: 10.11646/zootaxa.4701.5.

FIGURE 1. Ituglanis amphipotamus, MZUSP 69393 in A new species of Ituglanis Costa & Bockmann, 1993 (Siluriformes: Trichomycteridae) from Rio Ribeira de Iguape and upper Rio Tietê basins, southeastern Brazil

FIGURE 1. Ituglanis amphipotamus, MZUSP 69393, holotype, 70.3 mm SL; Brazil: São Paulo: Sete Barras, Rio Ipiranga, tributary of Rio Juquiá, Fazenda Brasban, Ribeira de Iguape drainage. Left lateral, dorsal and ventral views. Scale bars = 10 mm.Published as part of Mendonça, Marina Barreira, Oyakawa, Osvaldo Takeshi & Wosiacki, Wolmar Benjamin, 2018, A new species of Ituglanis Costa & Bockmann, 1993 (Siluriformes: Trichomycteridae) from Rio Ribeira de Iguape and upper Rio Tietê basins, southeastern Brazil, pp. 473-488 in Zootaxa 4504 (4) on page 476, DOI: 10.11646/zootaxa.4504.4.2, http://zenodo.org/record/260658