New tetra found in Rio Tocatins

A new species of characid has been described from the Rio Tocatins drainage in Brazil.

The tetra, which has been named Astyanax elachylepis has just been described by Vinicius Bertaco and Paulo Lucinda in the journal Neotropical Ichthyology.

Like many new fish discoveries, this one hasn\'t just been found in the field. The fish was found following an in-depth study of Astyanax species in spirit collections held at MCP (Museu de Ciencias e Tecnologia,

Pontificia Universidade Catolica do Rio Grande do Sul, Porto Alegre) and UNT (Universidade Federal do Tocantins, Porto Nacional) and was subsequently found to be a species new to science.

The discovery brings the total number of species in the Astyanax genus to around 87.

Astyanax elachylepis can be distinguished from other members of the genus by both its distinctive colouration and its morphology.

The fish has a large spot on the caudal peduncle, as well as one or two vertically-elongated humeral spots.

It also has 48-53 perforated scales in the lateral line series, 22-27 branched rays in the anal fin, and a single tooth on the maxillary.

Males, like many Astyanax species, do look a little different to females, with small hooks forming on the dorsal, anal and pelvic fins - presumably when the fish approaches sexual maturity.

For more details on the new tetra see the paper: VA. Bertaco and PHF Lucinda (2005) - Astyanax elachylepis, a new characid fish from the rio Tocantins drainage, Brazil (Teleostei: Characidae). Neotropical Ichthyology, 3(3):389-394, 2005.