New sexually dimorphic knifefish described


Scientists from Brazil and the USA have described a new species of sexually dimorphic electric knifefish from central, southern and coastal regions of Rio Grande do Sul state, Brazil, and Uruguay.

The new species is named Brachyhypopomus draco in a recent issue of the journal Neotropical Ichthyology, and can be distinguished from congeners by the extreme broadening of the distal portion of the caudal filament in males during the reproductive period to form a distinct paddle shaped structure, as well as relative proportions of the head and body parts.

Brachyhypopomus draco inhabits river edges, slow moving creeks, lagoons and flooded areas with muddy or sandy bottom and abundant emergent or floating vegetation, and is named after the shape of distal portion of caudal filament in mature males, similar to that illustrated in dragons.

For more information, see the paper: Giora, J, LR Malabarba and W Crampton (2008) Brachyhypopomus draco, a new sexually dimorphic species of Neotropical electric fish from southern South America (Gymnotiformes: Hypopomidae). Neotropical Ichthyology 6, pp. 159"168.