[Ichthyology • 2026] Molecular Phylogenetics and A New Taxonomy of the Neotropical Electric Fishes (Actinopterygii: Otophysi: Gymnotiformes)

 

Representatives of the six gymnotiform families Apteronotidae (A), Sternopygidae (S), Gymnotidae (G), Electrophoridae (E), Hypopomidae (H), and Rhamphichthyidae (R). 

Top to bottom, and left to right, are: Rhamphichthys rostratus (R), Archolaemus janeae (S), Sternarchorhamphus muelleri (A), Eigenmannia magoi (S), Gymnotus carapo (G), Sternarchorhynchus sp. (A), Apteronotus galvisi (A), Orthosternarchus tamandua (A), “Apteronotus” (Genus B) cuchillejo (A), Apteronotus eschmeyeri (A), Apteronotus cf. albifrons (A), Gymnorhamphichthys sp. (R), Sternarchorhynchus marreroi (A), Sternopygus aequilabiatus (S), Adontosternarchus devenanzii (A), Steatogenys duidae (R), Brachyhypopomus occidentalis (H), Hypopomus artedi (H), and Electrophorus multivalvulus (E). 

in Janzen, Sabaj, Crampton et Lovejoy, 2026.

DOI: doi.org/10.1016/j.ympev.2026.108678 

Photos by M. Sabaj.

  

Highlights: 

• New 9 gene molecular tree for 202 species of Neotropical electric knifefishes (order Gymnotiformes)

• A new taxonomy is proposed, based on the most extensive phylogenetic analysis to date.

• Strong phylogenetic support for 6 families, including the Electrophoridae (electric eels)

• Two main groups of species defined by either pulse or wave-type electric signals.

• Two new suborders: Pulseoidei for pulse-type species and Sinusoidei for wave-type species.

Abstract

The order Gymnotiformes—Neotropical electric eels and knifefishes—comprise a distinctive lineage of freshwater fishes characterized by electrogenesis and electroreception. Despite their ecological, evolutionary, and neurobiological significance, phylogenetic relationships within the order remain incompletely resolved. We present the most taxonomically inclusive molecular phylogeny of Gymnotiformes to date, based on two mitochondrial and seven nuclear genes from 202 species representing 31 of 36 extant genera. Maximum likelihood and Bayesian inference analyses provide strong support for a concordant species-level phylogenetic arrangement that we use to propose a revised classification of Gymnotiformes, including new suprageneric names and reassignments of some taxa and species. We found support for six monophyletic families, including Electrophoridae (electric eels). We propose two new suborders corresponding to electric signal type: Pulseoidei (pulse-type) and Sinusoidei (wave-type), an arrangement that does not allow determination of whether a pulse or wave-type signal was ancestral. In Apteronotidae, the subfamilies Sternarchorhamphinae and Apteronotinae are supported; within Apteronotinae, we establish the tribe Steatogenini to include Porotergus, Sternarchella, and close relatives. We resolve the non-monophyly of Apteronotus with generic reassignments. For Sternopygidae, we support the monophyletic subfamilies Sternopyginae and Eigenmanniinae and resolve polyphyly in Rhabdolichops and Eigenmannia via generic reassignments. Within Gymnotus, we support six species groups. We confirm the sister-group relationship between Hypopomidae and Rhamphichthyidae and clarify their internal structure, including support for six species groups within the diverse genus Brachyhypopomus. Our study provides a robust phylogenetic framework for Gymnotiformes and establishes a foundation for future work on systematics, biogeography, trait evolution, and comparative neurobiology.

 

Keywords: Neotropical, Systematics, Electric eel, Knifefish, Electric organ discharges

Sinusoidei subord. nov. changed from “Sinusoidea” of Albert 2001

Pulseoidei subord. nov. changed from “Pulseoidea” of Alda et al. 2018

Representatives of the six gymnotiform families Apteronotidae (A), Sternopygidae (S), Gymnotidae (G), Electrophoridae (E), Hypopomidae (H), and Rhamphichthyidae (R). 

Top to bottom, and left to right, are: Rhamphichthys rostratus (R), Archolaemus janeae (S), Sternarchorhamphus muelleri (A), Eigenmannia magoi (S), Gymnotus carapo (G), Sternarchorhynchus sp. (A), Apteronotus galvisi (A), Orthosternarchus tamandua (A), “Apteronotus” (Genus B) cuchillejo (A), Apteronotus eschmeyeri (A), Apteronotus cf. albifrons (A), Gymnorhamphichthys sp. (R), Sternarchorhynchus marreroi (A), Sternopygus aequilabiatus (S), Adontosternarchus devenanzii (A), Steatogenys duidae (R), Brachyhypopomus occidentalis (H), Hypopomus artedi (H), and Electrophorus multivalvulus (E). 

Photos by M. Sabaj.

  

 

 Francesco H. Janzen, Mark H. Sabaj, William G.R. Crampton, Nathan R. Lovejoy, 2026. Molecular Phylogenetics and A New Taxonomy of the Neotropical Electric Fishes (Actinopterygii: Otophysi: Gymnotiformes). Molecular Phylogenetics and Evolution. In Press, 108678. DOI: doi.org/10.1016/j.ympev.2026.108678 [10 July 2026]

[Ichthyology • 2026] Sternopygus embera • Towards Deconstruction of the Sternopygus macrurus species complex (Gymnotiformes: Sternopygidae): Description of A New Species from the Pacific Coast of Colombia

 

Sternopygus embera 

Torgersen, Galindo-Cuervo, Ortega-Lara, Lujan, Reis & Albert, 2026 

DOI: doi.org/10.11646/zootaxa.5748.4.5 

 Researchgate.net/publication/399770371

Abstract

A new species of longtail electric knifefish, Sternopygus embera sp. nov., is described from the trans-Andean Río Baudó and Río San Juan basins of the Pacific coast of northwestern Colombia. The new species is diagnosed from all congeners by a unique combination of characters, including the complete lack of a humeral spot, morphology of the Weberian apparatus, lack of pigment bars or saddles, possession of endopterygoid teeth, vertically-oriented ascending endopterygoid process, a short snout, convex dorsal margin of neurocranium in adults, and 22–23 precaudal vertebrae. Despite sharing more external morphological similarities with species of the S. macrurus complex, the new species is phylogenetically nested within the larger-bodied and longer-snouted trans-Andean S. aequilabiatus species group, based on phylogenetic analysis of the mitochondrial barcode gene. Alternative hypotheses for these contrasting results, including mitochondrial introgression, incomplete lineage sorting, and paedomorphosis, are discussed. The description of this species is a step towards deconstructing the S. macrurus complex ahead of a future systematic revision.

Pisces, río Baudó, Chocó, freshwater, knifefish, río San Juan, taxonomy, Trans-Andean region

Holotype of Sternopygus embera, CZUT-IC 28654, 326 mm TL, 264 mm LEA. Scale bars = 1 cm.

Live Sternopygus embera CZUT-IC 28654, holotype, from the Río Baudó basin immediately after capture.

Sternopygus embera Torgersen, Galindo-Cuervo, Ortega-Lara, Lujan, Reis, & Albert, new species

Etymology. The specific epithet honors the Emberá, an Indigenous people native to the Chocó region of westernColombia, where the new species occurs. The name acknowledges the deep connection of the Emberá people withthe region’s rivers and ecosystems. A noun in apposition.

 

Kevin T. TORGERSEN, Aleidy M. GALINDO-CUERVO, Armando ORTEGA-LARA, Nathan K. LUJAN, Roberto E. REIS and James S. ALBERT. 2026. Towards Deconstruction of the Sternopygus macrurus species complex (Gymnotiformes: Sternopygidae): Description of A New Species from the Pacific Coast of Colombia.  Zootaxa. 5748(4); 539-560. DOI: doi.org/10.11646/zootaxa.5748.4.5 [2026-01-15]  

 Researchgate.net/publication/399770371_Towards_deconstruction_of_the_Sternopygus_macrurus_species_complex_Description_of_a_new_species_from_the_Pacific_Coast_of_Colombia

[Ichthyology • 2024] Eigenmannia macuxi • Integrative Taxonomy reveals A New Species of the Glass Knifefish Genus Eigenmannia (Gymnotiformes: Sternopygidae) from the Rio Branco Basin, Brazil

 

Eigenmannia macuxi

 Dutra, Peixoto, Donin, Santana & Menezes, 2024

DOI: 10.1111/jfb.15794 

Researchgate.net/publication/381480976

Abstract

A new species of Eigenmannia is described from the Rio Branco basin, Roraima, Brazil, based on morphological and molecular datasets. It is distinguished from all congeners by the following combination of characters: lateral line stripe extending from first perforated lateral line scale to distal portion of caudal filament, presence of superior midlateral stripe with origin posterior to end of body cavity anal-fin hyaline, caudal filament corresponding to 15.2%–43.1% LEA, subterminal mouth, ii,14–16 pectoral-fin rays, 166–219 anal-fin rays, 10–13 scale rows above lateral line at vertical through posterior tip of pectoral fin, 100–128 scales on lateral line, 22–28 premaxillary teeth, 19–23 dentary teeth, 7–10 endopterygoid teeth, depth of posterodorsal expansion on infraorbitals 1 + 2 half as long as infraorbitals 1 + 2 length, basibranchial 1 unossified, 13 precaudal vertebrae, and length of coronomeckelian bone corresponding to 20% of Meckel's cartilage length. The new species has significant genetic divergence from species with accessible DNA sequences in public repositories, ranging from 10.8% to 17.7%. An osteological description of the new species, a review of Eigenmannia cytochrome c oxidase subunit I (COI) sequences available in public repositories based on voucher examination, and a hypothesis of phylogenetic relationships for the new species based on COI are provided. The critical importance of including voucher examination as one of the steps in the pipeline for using DNA sequences present in public repositories in taxonomic and phylogenetic studies is discussed.

Eigenmannia macuxi, MZUSP 129866, holotype,106.7 mm LEA, Cachoeira do Bem Querer, Rio Branco basin, Roraima, Brazil;  
(a) lateral view of head; (b) lateral view of body

Eigenmannia macuxi sp. nov.

Etymology: The epithet “macuxi” is in reference to the indigenous people whose home territory is near the type locality of the new species in Roraima, Brazil. A noun in apposition. 

Guilherme Moreira Dutra, Luiz Antônio Wanderley Peixoto, Laura Modesti Donin, Carlos David de Santana and Naercio Aquino Menezes. 2024. Integrative Taxonomy reveals A New Species of the Glass Knifefish Genus Eigenmannia Jordan & Evermann, 1896 (Teleostei: Gymnotiformes: Sternopygidae) from the Rio Branco Basin, Brazil. Journal of Fish Biology. DOI: 10.1111/jfb.15794 

Researchgate.net/publication/381480976_Integrative_taxonomy_reveals_a_new_species_of_the_Eigenmannia_from_the_Rio_Branco_basin_Brazil

  x.com/JamesAl0410008/status/1803768276540916118

 

[Ichthyology • 2022] Sternopygus sabaji • A New Species of Sternopygus (Gymnotiformes: Sternopygidae) from the Atlantic Coast of the Guiana Shield

Sternopygus sabaji 

Torgersen & Albert, 2022

DOI: 10.1643/i2022013 

 twitter.com/IchsAndHerps

Abstract

Sternopygus sabaji, new species, is described from the Atlantic drainages of the Guiana Shield region of South America using traditional methods of morphometrics and meristics and microcomputed tomography (µCT) scans for osteological analysis. The new species is diagnosed from all other species of Sternopygus by the lack of dentition on the anteroventral surface of the endopterygoid and by the possession of a wider mouth. It further differs from its congeners by the following combination of characters: reduced humeral spot with low-contrast and poorly defined margins, possession of a light-colored mid-lateral stripe along posterior portion of lateral line, possession of 1–3 dark saddle-like markings along dorsum of smaller individuals, and a relatively low precaudal vertebrae count. This work provides the first description of a species of Sternopygus that is endemic to the Guiana Shield, joining S. astrabes and S. macrurus in elevating the species richness of the clade in that region to three species and the total number of valid Sternopygus to ten species.

Sternopygus sabaji, holotype, ANSP 208090 (374 mm TL).
 (A) Full body view; (B) closeup of head. Position of anus and urogenital papilla indicated by arrow.

Scale bar = 1 cm.

Paratype specimen of Sternopygus sabaji ANSP 189018 (146 mm TL).
(A) Specimen with live coloration, photo taken after collection in 2007.
 (B) Same specimen with preserved coloration photographed in 2021.

Scale bar = 1 cm. Photo of specimen with live coloration by Mark Sabaj.

Sternopygus sabaji, new species

Etymology.—This species is named in honor of Dr. Mark Henry Sabaj, of the Academy of Natural Sciences, Philadelphia, for his many contributions to the exploration and understanding of Neotropical aquatic diversity. The authors also acknowledge his role in collecting and photographing the specimens of the type series and his help to the authors in obtaining specimen loans for this study. 

Distribution.— Sternopygus sabaji is known from the Marowijne (Maroni) and Essequibo drainage basins where it is found sympatrically with S. macrurus and possibly another undescribed member of the genus (Fig. 10).

 

 

Kevin T. Torgersen and James S. Albert. 2022. A New Species of Sternopygus (Gymnotiformes: Sternopygidae) from the Atlantic Coast of the Guiana Shield. Ichthyology & Herpetology. 110(4), 714-727. DOI: 10.1643/i2022013 

 twitter.com/IchsAndHerps/status/1589645981225582592

[Ichthyology • 2022] Eigenmannia bumba, E. cacuria & E. robsoni • Three New Species of Eigenmannia (Gymnotiformes: Sternopygidae) from the rio Mearim and rio Parnaíba basins, Northeastern Brazil

Eigenmannia bumba (white), E. cacuria (black),

and E. robsoni (red). A star indicates the type locality.

Dutra, Ramos & Menezes, 2022

 ni.bio.br/1982-0224-2021-0117

Abstract​ 

Three new species of Eigenmannia belonging to the E. trilineata species-group are described. The first species is described from rio Mearim basin and can be diagnosed by lateral line stripe restricted to last two thirds of body, superior midlateral stripe present, 176–205 anal-fin rays, 10–15 scales rows above lateral line, 109–125 lateral line scales, 19–23 premaxillary teeth, 20–29 dentary teeth, 6–10 endopterygoid teeth, and 13–14 precaudal vertebrae. The second species is described from upper rio Parnaíba, and can be diagnosed by lateral line stripe restricted to last two-thirds of body, ii,11–13 pectoral-fin rays, 180–196 anal-fin rays, 12–15 scales rows above lateral line, 10–14 premaxillary teeth, 15–21 dentary teeth, 8–10 endopterygoid teeth, and 14 precaudal vertebrae. The third species is widespread in rio Parnaíba basin, and can be diagnosed by absence of lateral line stripe, absence of superior midlateral stripe, 182–228 anal-fin rays, 12–15 scales rows above lateral line, 107–131 lateral line scales, 32–34 premaxillary teeth, 35–44 dentary teeth, 9–12 endopterygoid teeth, and 13 precaudal vertebrae. A dichotomous key and the conservation status for the three species are provided.

Keywords: Electric fishes, Eigenmannia trilineata species-group, Identification key, Taxonomy.

Map of Northern Brazil showing distribution of Eigenmannia bumba (white), Eigenmannia cacuria (black), and E. robsoni (red). A star indicates the type locality.

Eigenmannia bumba, MZUSP 125870, holotype, 117.5 mm LEA, 

rio Santana, Grajaú, Maranhão, Brazil. 

A. lateral view of head, B. lateral view of body.

Eigenmannia cacuria, MZUSP 125871, 

holotype, 110.0 mm LEA, 

riacho Enxada, Alto Parnaíba, Maranhão. 

A. lateral view of head, B. lateral view of body.

Eigenmannia bumba, new species

Etymology. The epithet “bumba” is in reference to “bumba meu boi” or “boi-bumbá”, a folklore character in Northern Brazil. A noun in apposition.

Eigenmannia cacuria, new species

Etymology. The epithet “cacuria” is in reference to the “cacuriá”, a typical dance in the state of Maranhão, where the holotype was collected. A noun in apposition.

Eigenmannia robsoni, MZUSP 125872, holotype, 139.3 mm LEA,
rio Parnaíba, Muricí dos Portelas, Piauí.
A. lateral view of head, B. lateral view of body.

Eigenmannia robsoni, new species

Etymology. The epithet “robsoni” is in honor of Robson Tamar da Costa Ramos, ichthyologist, for his contributions to studies of the Caatinga ecoregion, especially in the Parnaíba river basin. A patronym.

 Guilherme Moreira Dutra, Telton Pedro Anselmo Ramos and  Naércio Aquino Menezes. 2022. Description of Three New Species of Eigenmannia (Gymnotiformes: Sternopygidae) from the rio Mearim and rio Parnaíba basins, Northeastern Brazil. Neotrop Ichthyol. 20(1);e210117.  DOI: 10.1590/1982-0224-2021-0117 

ni.bio.br/1982-0224-2021-0117/

 twitter.com/Neotropi/status/1510383920335962117

    

[Ichthyology • 2019] Eigenmannia sirius • A New Species of Eigenmannia Jordan & Evermann (Gymnotiformes: Sternopygidae) from rio Tapajós, Brazil, with Discussion on Its Species Group and the Myology within Eigenmanniinae

Eigenmannia sirius

 Peixoto & Ohara, 2019

  DOI: 10.1371/journal.pone.0220287

Abstract

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.

  

Fig 1. Lateral view of Eigenmannia sirius, MZSUP 121668, holotype, 127.5 mm LEA, Mato Grosso, Brazil, rio Mutum, tributary of rio Juruena, rio Tapajós basin. 

Fig 5. Color in life of Eigenmannia sirius, MZUSP 123938, paratypes, 93.7 and 77.3 mm LEA, A and B respectively, rio Mutum, rio Juruena, Mato Grosso, Brazil. Caudal filament damaged.

Eigenmannia sirius, sp. nov. 

Diagnosis: Eigenmannia sirius is diagnosed from all putative congeners with exception of Eigenmannia trilineata species-group (sensu [Peixoto, et al., 2015]), by the presence of superior midlateral stripe (vs. absence). The new species differs from all species of the Eigenmannia trilineata species-group, except E. besouro, E. correntes, E. vicentespelaea, and E. waiwai, by the subterminal mouth (vs. terminal). It differs from E. besouro, E. correntes, E. vicentespelaea, and E. waiwai by relative depth of posterodorsal expansion on infraorbitals 1+2 corresponding to 70% length of infraorbitals 1+2 (Fig 2—vs. 40% in E. besouro, E. correntes and E. waiwai, and approximately equals total length of infraorbitals 1+2 in E. vicentespelaea), and in having 15 precaudal vertebrae (vs. 14 in E. besouro and E. correntes, 13–14 in E. vicentespelaea and 12–13 in E. waiwai). Eigenmannia sirius can be differentiated from E. besouro by the origin of the superior midlateral stripe at vertical between base of 23rd to 31st anal-fin ray (vs. origin at vertical between 5th to 15th anal-fin ray). The new species is also diagnosed from E. correntes by the eye diameter (17.2–23.8% HL vs. 10.6–13.3% HL), and by the mouth width (13.1–22.4% HL vs. 23.5–26.0% HL). Eigenmannia sirius is further distinguished from E. vicentespelaea and E. waiwai by having 15–24 premaxillary teeth (Fig 3A vs. 25–26 and 35–40, respectively) and 15–33 dentary teeth (Fig 3B vs. 38–45 and 37–38, respectively). It additionally differs from E. vicentespealea by having 9–12 scale rows above lateral line (vs. seven or eight) and the coronomeckelian bone corresponding to 20–25% of length of Meckel’s cartilage (Fig 3B vs. 45%). The new species can be distinguished from Archolaemus species by the eye completely covered by thin membrane (vs. a free orbital rim); from Distocyclus by the rounded snout in profile (vs. conical snout); from Japigny by the absence of alternating dark bands on flanks (vs. presence); and from Rhabdolichops by the region above the lateral line on the anterior portion of the body covered by scales (vs. absence of scales above the lateral line on the anterior portion of the body).

Etymology: The specific epithet sirius is an allusion to the alpha star of the Canis Major constellation that represents the state of Mato Grosso in the Brazilian national flag, a reference of the state of occurrence of the new taxon. A noun in apposition.

Fig 10. Photograph of rio Mutum, type locality of Eigenmannia sirius, illustrating habitat.

Distribution and habitat: Eigenmannia sirius is currently known only from rio Mutum, a tributary of the upper rio Juruena, rio Tapajós basin, Comodoro, Mato Grosso, Brazil (Fig 9). The type-locality is 502 m above sea level at the Chapada dos Parecis plateau. It is a clearwater river up to c. 3–6 m wide and 0.5–2.5 m deep, preserved riparian vegetation, swift current, and sand, pebbles and dead leaves on the bottom (Fig 10). Several types of microenvironment were sampled exhaustively, but E. sirius was captured only between root and subaquatic vegetation. Other species sampled syntopically were Aequidens cf. rondoni (Miranda Ribeiro), Erythrinus erythrinus (Bloch & Schneider), Hemigrammus skolioplatus Bertaco & Carvalho, Hyphessobrycon hexastichos Bertaco & Carvalho, H. melanostichos Carvalho & Bertaco, Hasemania nambiquara Bertaco & Malabarba, and Hoplerythrinus unitaeniatus (Spix & Agassiz). No other Gymnotiformes were collected with E. sirius.

Luiz Antônio Wanderley Peixoto and Willian M. Ohara. 2019. A New Species of Eigenmannia Jordan & Evermann (Gymnotiformes: Sternopygidae) from rio Tapajós, Brazil, with Discussion on Its Species Group and the Myology within Eigenmanniinae. PLoS ONE. 14(8): e0220287.  DOI: 10.1371/journal.pone.0220287

[Ichthyology • 2017] Eigenmannia sayona • A New Species of the Eigenmannia trilineata Species Group (Gymnotiformes: Sternopygidae) from the río Orinoco Basin, Venezuela

  Eigenmannia sayona

Peixoto & Waltz, 2017
DOI: 10.1590/1982-0224-20150199 

Abstract

A new species of the Eigenmannia trilineata species group is described from the río Orinoco basin, Venezuela. The new species is distinguished from congeners by a unique set of characters including an ossified basibranchial 1; 198-217 anal-fin rays; suborbital depth, 21.3-26.1% HL; length of anterodorsal process of maxilla equal to the width of the posterior nostril; premaxilla with 17 teeth distributed in three rows; hyaline pectoral and anal fins; and number of scale series above lateral line, 9-10. It raises the number of species allocated to the Eigenmannia trilineata species group to 13 and the number of species within the genus to 18.

Keywords: Biodiversity; Electric-fishes; Taxonomy; Tuvira.

Fig. 1 Holotype of Eigenmannia sayona, new species, MZUSP 96497, 131.8 mm LEA, Venezuela, Bolivar, Cedeño, río Orinoco, río Parguaza, near the community of Puente Parhueña. a. Lateral view of head and body; b. Lateral view of head. 

Etymology. The specific epithet “sayona” is assigned to the new species in reference to “La Sayona”, a spirit of philanderous vengeance in Venezuelan lore. A noun in apposition.

Geographic distribution. Eigenmannia sayona is known from río Orinoco basin, from río Parguaza, río Apure, and Laguna de Castilleros, Venezuela.

Luiz A. W. Peixoto and Brandon T. Waltz. 2017. A New Species of the Eigenmannia trilineata (Gymnotiformes: Sternopygidae) Species Group from the río Orinoco Basin, Venezuela. Neotropical Ichthyology. 15(1); e150199. DOI: 10.1590/1982-0224-20150199.

[Ichthyology • 2017] Eigenmannia meeki • A New Species of the Glass Electric Knifefish Genus Eigenmannia Jordan and Evermann (Gymnotiformes: Sternopygidae) from Río Tuíra Basin, Panama

Eigenmannia meeki  

Dutra, de Santana & Wosiacki, 2017

  DOI: 10.1643/CI-16-439 

A new species of Eigenmannia is described from the Río Pucuro, Río Tuíra 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.

Fig. 1. Eigenmannia meeki, USNM 293171, holotype, 235.7 mm LEA, Panama, Darien, Río Púcuro, Río Tuíra basin.

  DOI: 10.1643/CI-16-439  

Distribution.— Eigenmannia meeki is known from its type locality in the Río Púcuro, and Río Chucunaque in the Río Tuíra basin, Darien Province, Panama (Fig. 5). 

 Etymology.— The specific epithet, meeki, is in honor of Seth Eugene Meek (1859–1914) who made many contributions to the knowledge of the diversity of the fishes of Panama

Guilherme Moreira Dutra, Carlos David de Santana and Wolmar Benjamin Wosiacki. 2017.  A New Species of the Glass Electric Knifefish Genus Eigenmannia Jordan and Evermann (Teleostei: Gymnotiformes: Sternopygidae) from Río Tuíra Basin, Panama.   

 Copeia. 105(1); 85-91.  DOI: 10.1643/CI-16-439

Una nueva especie de Eigenmannia es descrita del río Pucuro, que pertenece a la cuenca del Río Tuíra, Panamá. Esta diagnosticada de las demás especies del género por la posición de la boca, el padrón de coloración, el número de radios de la aleta anal, el número de escamas de la línea lateral, el número de hileras de escamas arriba de la línea lateral, el número y disposición de los dientes en el hueso dentario, el número de vertebras pre-caudales, el tamaño relativo de la expansión postero-dorsal del hueso infraorbital 1+2 y el tamaño relativo del hueso corono-meckeliano. Esta nueva especie es la primera Eigenmannia descrita de las cuencas de América Central y además es la especie con la distribución más boreal del género.

[Ichthyology • 2016] Eigenmannia correntes • A New Species of Eigenmannia Jordan and Evermann (Gymnotiformes: Sternopygidae) from the upper rio Paraguai basin, Brazil

Eigenmannia correntes 

  Campos-da-Paz & Queiroz, 2017  

DOI:  10.11646/zootaxa.4216.1.5

Abstract

Eigenmannia correntes, a new species belonging to the Eigenmannia trilineata species-group, is described from tributaries of rio Correntes, a major affluent of the rio Piquiri system, upper rio Paraguai basin (Mato Grosso and Mato Grosso do Sul states, Brazil). Eigenmannia correntes is included in the currently poorly defined sternopygid genus Eigenmannia (Ostariophysi: Gymnotiformes) by presenting characters that are either primitive or of uncertain polarity, such as eyes covered by skin, scales present over entire postcranial portion of body, teeth absent from oral valve, infraorbital bones 1+2 with enlarged posterodorsal expansion, and gill rakers short and unossified. The new species is distinguished from all congeners, except those species included in the Eigenmannia trilineata species-group, by the presence of a conspicuous superior midlateral stripe (synapomorphy of this clade). Eigenmannia correntes can be differentiated from all members of the Eigenmannia trilineata species-group, except E. vicentespelaea, E. waiwai and E. besouro, by its subterminal mouth (vs. terminal in remaining species of that group). Further, it differs from these aforementioned species by a number of meristic and morphometric characters, including number of premaxillary and dentary teeth, number of longitudinal series of scales above lateral line, number of pectoral-fin and anal-fin rays, eye diameter, postorbital distance, and snout length. Finally, notes on reproduction and parasitism for E. correntes are presented.

Keywords: Pisces, Eigenmannia trilineata, Eigenmanninae, glass knifefish, Systematics, taxonomy

Etymology. The specific epithet correntes refers to the rio Correntes, the main river at the rio Piquiri system, upper rio Paraguai basin, from where all specimens used in the original description were collected. A noun in apposition.

Ricardo Campos-Da-Paz and Igor Raposo Queiroz. 2017. A New Species of Eigenmannia Jordan and Evermann (Gymnotiformes: Sternopygidae) from the upper rio Paraguai basin.
Zootaxa. 4216(1); 073–084.   DOI:  10.11646/zootaxa.4216.1.5

[Ichthyology • 2016] Eigenmannia besouro • A New Species of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae) from the rio São Francisco basin, northeastern Brazil

Eigenmannia besouro 

Peixoto & Wosiacki, 2016

 DOI: 10.11646/zootaxa.4126.2.6 

Abstract

A new species of the Eigenmannia trilineata species-group is described from the rio São Francisco basin, Brazil. It is distinguished from closely related species by a unique set of characters, including a subterminal mouth, the presence of ii,13–14 pectoral-fin rays, a coronomeckelian bone that is 30% the length of Meckel’s cartilage, the specific pattern of the dentition of the premaxilla and dentary, and the more anterior origin of the superior midlateral stripe. Comments on species of the E. trilineata species-group are presented.

Keywords: Pisces, diversity, glass knifefish, electric fish, species group

FIGURE 1. Eigenmannia besouro, MZUSP 57890, holotype, 91.9 mm LEA, Brazil, Bahia, São Desidério, rio São Francisco, rio Grande. (A) Left lateral view of body; (B) Head. 

Distribution. Eigenmannia besouro is known from tributaries of the left margin of rio São Francisco, Bahia, northeastern Brazil (Fig. 5).

Etymology. The species name, besouro (‘beetle’ in Portuguese) is in honor of Manoel Henrique Pereira, known as Besouro Mangangá (‘The Mangangá Beetle’), a native of the Recôncavo region of Bahia, and a legendary figure in the Afro-Brazilian martial art capoeira; a noun in opposition.

Peixoto, Luiz A. W. & Wolmar B. Wosiacki. 2016. Eigenmannia besouro, A New Species of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae) from the rio São Francisco basin, northeastern Brazil. Zootaxa. 4126(2); 262–270.  DOI: 10.11646/zootaxa.4126.2.6

researchgate.net/publication/304032886_Eigenmannia_besouro_a_new_species_of_the_Eigenmannia_trilineata_species-group_Gymnotiformes_Sternopygidae_from_the_rio_Sao_Francisco_basin_northeastern_Brazil

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[Ichthyology • 2006] Morphology and Distribution of the Cave Knifefish Eigenmannia vicentespelaea Triques, 1996 (Gymnotiformes: Sternopygidae) from Central Brazil, with an expanded Diagnosis and comments on Subterranean Evolution

(upper) Living specimen of Eigenmannia vicentespelaea with relatively well developed eyes and translucent aspect. Note the three longitudinal stripes (LEA: 121.9 mm). Photo: José Sabino.
(lower) Sinkhole of São Vicente Cave System, São Domingos karst area, Goiás State, Central Brazil – type locality of Eigenmannia vicentespelaea Triques, 1996. Photo: E. M. Bichuette

We present herein data on morphology and distribution of the cave knifefish Eigenmannia vicentespelaea Triques, 1996, from the São Domingos karst area, Central Brazil, comparing it to the epigean (surface) species, Eigenmannia sp., found in the same area (but not syntopic with E. vicentespelaea) and also with congeners from other localities. Collecting sites comprising epigean and subterranean stream reaches in São Domingos were sampled during the dry seasons of 1999, 2000, and 2001 using several methods. Preserved specimens of E. vicentespelaea (n=25, including holotype and paratype) and of Eigenmannia sp. (n=15) were compared with focus on morphometric characters, body pigmentation and eye condition. A combination of characters separates E. vicentespelaea from Eigenmannia sp. and other congeners: the length from the tip of the snout to the posterior of the anal fin base, ocular diameter: head length and pre-anal distance: head length proportions, and body pigmentation. A wider morphometric variation in E. vicentespelaea is described than that reported in the original description (based on two specimens).

Key words: Morphometric data, electric fishes, cave environment, São Domingos karst area.

Maria Elina Bichuette and Eleonora Trajano. 2006. Morphology and Distribution of the Cave Knifefish Eigenmannia vicentespelaea Triques, 1996 (Gymnotiformes: Sternopygidae) from Central Brazil, with an expanded Diagnosis and comments on Subterranean Evolution. Neotropical Ichthyology. 4(1); 99-105

http://scielo.br/pdf/ni/v4n1/v4n1a11.pdf