Abstract
Seven new species of Gymnotus are described, and a redescription of the type species G. carapo sensu-stricto Linnaeus (G. carapo s.s.) is provided, from examination of populations from throughout tropical South and Middle America. The new species are described on the basis of unique combinations of characters. Five of the new species are members of the G. carapo species-group: 1, Gymnotus choco n. sp., from the Baudó and Atrato basins on the Pacific and Caribbean slopes of Colombia; 2, Gymnotus esmeraldas n. sp., from the Esmeraldas and Guayaquil basins on the Pacific Slope of Ecuador; 3, Gymnotus henni n. sp., from the Calima and Juradó basins on the Pacific Slope of Colombia; 4, Gymnotus paraguensis n. sp., from the Paraguay basin; 5, Gymnotustigre n. sp., from the Amazon basin of Ecuador, Peru and Brazil. Two of the new species are members of the G. pantherinus species-group: 1, Gymnotus javari n. sp., from the Amazon, Napo, Javarí, and Ucayali basins; 2, Gymnotus panamensis n. sp., from Atlantic slope of western Panama. Gymnotus carapo s.s. is restricted to the Amazon and Orinoco basins, the Island of Trinidad, the coastal basins of the Guianas, and the Brazilian state of Piauí. Six allopatric populations of G. carapo s.s are recognized from differences in the mean, modal or median values of morphometric and meristic traits: 1, Eastern Amazon; 2, Parnaíba and Itapicuru basins; 3, Branco basin; 4; Guiana Shield, Orinoco basin and Island of Trinidad; 5, Madeira basin of Brazil, Bolivia and Peru; 6, Western Amazon basin of Brazil, Colombia, Ecuador, and Peru. Four of the new species representing both the G. carapo and G. pantherinus species-groups inhabit waters to the west of the Andean Cordillera. The biogeographic distributions of these species-groups suggest origins and early diversification before the most recent Andean orogeny, c. 8–12 mya.
References
Albert, J.S. (2001) Species diversity and phylogenetic systematics of American knifefishes (Gymnotiformes, Teleostei). Miscellaneous Publications Museum Zoology, University of Michigan, 190, 1–127.
Albert, J.S. & Crampton, W.G.R. (2001) Five new species of Gymnotus (Gymnotiformes, Teleostei) from an Upper Amazonian floodplain, with descriptions of electric organ discharges and ecology. Ichthyological Exploration Freshwaters, 12, 241–266.
Albert, J.S., Fernandes-Matioli, F.M. & de Almeida-Toledo, L.F. (1999) A new species of Gymnotus (Gymnotiformes, Teleostei) from southeastern Brazil: Towards the deconstruction of Gymnotus carapo. Copeia, 1999, 410–421.
Albert, J.S. & Fink, W.L. (1996) Sternopygus xingu, a new species of electric fish (Gymnotoidei, Teleostei), from South America, with comments on the phylogenetic position of Sternopygus. Copeia, 1996, 85–102.
Albert, J.S. & Miller, R.R. (1995) Gymnotus maculosus: a new species of electric fish from Middle America (Teleostei: Gymnotoidei), with a key to the species of Gymnotus. Proceedings Biological Society Washington, 108, 662–678.
Alves-Gomes, J.A. (1997) Informações preliminares sobre a bio-ecologia de peixes elétricos (Ordem Gymnotiformes) em Roraima. In: Barbosa, R.I., Ferreira, E.F., & Castellón, E.G. (Ed) Homen, Ambiente e Ecologia no Estado de Roraima, INPA, Manaus, pp. 509–553.
Artedi, P. (1738) Ichthyologia sive Opera Omnia de Piscibus. Bloch, M.E. (1786) Naturgeschichte der Auslandischen Fische. Berlin. v. 3: i-xii + 1–146, Pls. 181–216.
Campos-da-Paz, R. (2000) Taxonomic status of Rhamphichthys cingulatus Brind and a more precise assignment of the type-locality of Gymnotus coatesi LaMonte (Ostariophysi : Gymnotiformes). Copeia, 2000, 1114–1117.
Campos-da-Paz, R. (2002) Gymnotus diamantinensis, a new species of electric knifefish from upper rio Arinos basin, Brazil (Ostariophysi: Gymnotidae). Ichthyological Exploration Freshwaters, 13, 185–192.
Campos-da-Paz, R. & Costa,W.J.E.M. (1996) Gymnotus bahianus n. sp., a new gymnotid fish from eastern Brazil (Teleostei: Ostariophysi: Gymnotiforms), with evidence for the monophyly of the genus. Copeia, 1996, 937–944.
Crampton, W.G.R. (1996a) Gymnotiform fish: an important component of Amazonian flood plain fish communities. Journal of Fish Biology, 48, 298–301.
Crampton, W.G.R. (1996b) The Electric Fish of the Upper Amazon: Ecology and Signal Diversity, unpublished Doctoral thesis. Department of Zoology. The University of Oxford, Oxford, pp. 1– 223.
Crampton, W.G.R. (1998) Electric signal design and habitat preferences in a species rich assemblage of gymnotiform fishes from the Upper Amazon Basin. Anais da Academia Brasileira de Ciências, 70, 805–847.
Da Silva, M.N.F. & Patton, J.L. (1998) Molecular phylogeography and the evolution and conservation of Amazonian mammals. Molecular Ecology, 7, 475–486.
Ellis, M.M. (1913) The gymnotid eels of tropical America. Memoirs of the Carnegie Museum, 6, 109–195.
Fernandes-Matioli, F.M.C. & Almeida-Toledo, L.F. (2001) A molecular phylogenetic analysis in Gymnotus species (Pisces: Gymnotiformes) with inferences on chromosome evolution. Caryologia, 54, 23–30.
Fernandes-Matioli, F.M.C., Almeida-Toledo, L.F. & Toledo, S.A. (1998a) Natural triploidy in the Neotropical species Gymnotus carapo (Pisces : Gymnotiformes). Caryologia, 51, 319–322.
Fernandes-Matioli, F.M.C., Marchetto, M.C.N., Almeida-Toledo, L.F. & Toledo, S.A. (1998b) High intraspecific karyological conservation in four species of Gymnotus (Pisces : Gymnotiformes) from southeastern Brazilian basins. Caryologia, 51, 221–234.
Fernandes-Matioli, F.M.C.,Matioli, S.R. & Almeida-Toledo, L.F. (2000) Species diversity and geographic distribution of Gymnotus (Pisces: Gymnotiformes) by nuclear (GGAC)(n) microsatellite analysis. Genetics and Molecular Biology, 23(4), 803–807.
Fernholm, B. & Wheeler, A. (1983) Linnaean fish specimens in the Swedish Museum of Natural History, Stockholm. Zoological Journal Linnean Society, 78, 199–286.
Hoedeman, J.J. (1962) Notes on the ichthyology of Surinam and other Guianas. 11. New gymnotiform fishes from Surinam and French Guiana, with additional records and a key to the groups and species from Guiana. Bulletin Aquatic Biology Amsterdam, 3, 97–107.
Holthuis, L.B. (1959) The Crustacea Decapoda of Suriname (Dutch Guiana). Leiden. Hoogmoed, M.S. (1973) Notes on the Herpetofauna of Surinam IV - The Lizards and Amphisbaenians of Surinam. Biogeographica, The Hague, Dr. W. Junk, 419 pp.
Ihering, R. von. (1914) Duas especies novas de Peixes da Fam. Cichlidae. Revista Museu São Paulo 9, 333–337.
Kirschbaum, F. & Wieczorek, L. (2002) Entdeckung einer neuen Fortpflanzungs-strategie bei südamerikainischen Messerfischen (Teleostei: Gymnotiformes: Gymnotidae): Maulbrüten bei Gymnotus carapo. Verhalten der Aquarienfische, 2, 99–107.
LaMonte, F.R. (1935) Two new species of Gymnotus. American Museum Novitates, 781, 1–3.
Lacépède, B.G.E. (1800) Histoire Naturelle des Poissons. Paris, v.2, 632 pp.
Leviton, A.E., Gibbs, R.H., Heal, E., & Dawson, C. E. (1985) Standards in herpetology and ichthyology: Part I. Standard symbolic codes for institutional resource collections in herpetology and ichthyology. Copeia, 1985, 802–832.
Liem K.F., Eclancher, B., & Fink W.L. (1984) Aerial respiration in the banded knife fish Gymnotus carapo (Teleostei, Gymnotoidei). Physiological Zoology, 57, 185–195.
Linnaeus, C. (1758) Systema Naturae, Ed. X. (Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.) Holmiae.
Lundberg, J.G. (1998). The temporal context for the diversification of Neotropical fishes. In: Malabarba, L., Reis, R.E., Vari, R.P., de Lucena, C.A.S. & de Lucena, Z.M.S. (Ed) Phylogeny and Classification of Neotropical Fishes, Porto Alegre, Museu de Ciências e Tecnologia, pp. 49– 68.
Lundberg, J.G., Cox Fernandes, C., Albert, J.S., & Garcia, M. (1996) Magosternarchus, a new genus with two new species of electric fish (Gymnotiformes: Apteronotidae) from the Amazon River basin, South America. Copeia, 1996, 657–670.
Lönnberg, E. (1896) Linnean type-specimens of birds, reptiles, batrachians and fishes in the Zoological Museum of the R. University in Upsala. Bihang Kongl. Svenska Vet.-Akad. Handl. v. 22, afd. 4, 1–45.
Mago-Leccia, F. (1994) Electric Fishes of the Continental Waters of America. Biblioteca de la Academia de Ciencias Fisicas, Matematicas, y Naturales, Caracas, 206 pp.
Marcgraf, G. (1648) Historiae rerum naturalium Brasiliae. Haak en Elsevier, Leiden and Amsterdam. Moritz, C. (1994) Applications of mitochondrial DNA analysis in conservation: a critical review. Molecular Ecology, 3, 401–411.
Nijssen, H. & Isbrücker, I.J.H. (1968) Gymnotus carapo and G. anguillaris syn. G. coropinae, two often confused species of gymnotid fishes (Pisces, Cypriniformes). Beaufortia 15, 161-168.
Northcutt, R.G., Holmes, P.H. & Albert, J.S. (2000) Distribution and innervation of lateral line organs of the Channel Catfish. Journal of Comparative Neurology, 421, 570–592.
Pallas, P.S. (1769) Spicilegia Zoologica quibus novae imprimis et obscurae animalium species iconibus, descriptionibus atque commentariis illustrantur. Berolini, 1, 1–42.
Ricklefs, R.E. (1989). Speciation and Diversity: The Integration of Local and Regional Processes. In: Otte, D. & Endler, J.A. (Ed) Speciation and Its Consequences, Sunderland, Sinauer Associates, pp. 599–624.
Taylor, W.R. & Van Dyke, G.C. (1985) Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium, 9, 107–119.
Wheeler, A. (1991) The Linnaean fish collection in the Zoological Museum of the University of Uppsala. Zoological Journal Linnean Society, 103, 145–195.