A Review of the South American Electric Fish Genus Porotergus (Gymnotiformes: Apteronotidae) with the Description of a New Species

The species currently assigned to the South American electric fish genus Porotergus are reviewed. Porotergus duende, a new species, is described from the lowland western Amazon basin in Brazil and Peru. Porotergus gimbeli from the lowland Amazon basin in Brazil and Peru, and P. gymnotus from the Essequibo drainage of Guyana are redescribed. Porotergus duende and P. gimbeli are restricted to deep channel habitats. Porotergus gymnotus occurs in shallow rivers. Notes on the ecology and electric organ discharge of P. duende and P. gimbeli are presented. A key to the members of the genus is provided.

Resumo

As espécies de peixes elétricos Sul Americanos do gênero Porotergus são revisadas. Porotergus duende, uma nova espécie, é descrita para a porção oeste da bacia Amazônica Brasileira e Peruana. Porotergus gimbeli que ocorre nas porções leste e oeste da bacia Amazônica Brasileira e Peruana, e P. gymnotus do rio Essequibo na Guiana são redescritas. Porotergus duende e P. gimbeli habitam os canais profundos dos rios. Porotergus gymnotus ocorre em rios de águas rasas. Notas sobre a ecologia e a descarga do órgão elétrico são fornecidas para P. duende e P. gimbeli. Uma chave para as espécies do gênero é apresentada.

Fig. 1

Head (live) and body (recently preserved) of Porotergus duende holotype, MCP 37357, 104.0 mm. Scale bars = 10 mm. Dorsal mid-saggital electroreceptive structure partially dislodged, as often occurs in preserved specimens but never in live fish.

Fig. 2

Geographic distribution of Porotergus duende (squares; 1 = type locality at Amazon River, near city of Tefé). Some symbols represent more than one lot or locality.

Fig. 3

Holotype of Porotergus gimbeli, FMNH 54566, 200.0 mm, reproduced from Ellis (1913).

Fig. 4

Porotergus gimbeli from the Amazon River, near the city of Tefé, showing sexual dimorphism in cranial morphology. (A) MCP 37527 (sexually mature male, 202.0 mm). (B) MCP 37525 (sexually mature female, 189.0 mm TL). Scale bar = 10 mm.

Fig. 5

Geographic distribution of Porotergus gimbeli (squares; precise type locality unknown, but possibly near the city of Belém do Pará [1]), and Porotergus gymnotus (dots; 2 = type locality at Essequibo River). Some symbols represent more than one lot or locality.

Fig. 6

Holotype of Porotergus gymnotus, FMNH 53575, 65.2 mm, reproduced from Ellis (1913). Note that Ellis registered a total length of 70.0 mm.

Fig. 7

Paratype of Porotergus gymnotus, CAS 62305 (85.0 mm), from Amatuk, Guyana. Scale bar = 10 mm.

Contributor Notes

Associate Editor: C. J. Ferraris.

¹ Department of Biology, University of Central Florida, Orlando, Florida 32816-2368; Research Collaborator, Division of Fishes, Department of Vertebrate Zoology, MCR-159, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20013-7012. Present address: Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Manaus, AM, Brazil; E-mail: apteronotidae@ig.com.br. Send reprint requests to this address.

² Department of Biology, University of Central Florida, Orlando, Florida 32816-2368.

Received: 15 Jun 2005

Accepted: 28 Oct 2009