© W. J. E. M. Costa

A new member of the genus Nematocharax from Bahia state, eastern Brazil is just the second member of the genus known to date.

Named in honour of Brazilian ichthyologist Wilson Costa, who was the first to recognise the new species in the field, Nematocharax costai has only been collected at the type locality which comprises a fast-flowing stream with sandy substrate and pale brown water.

It can be told apart from its only congener, N. venustus Weitzman et al., 1986, by lacking hooks and spinules on the dorsal and pelvic fins (vs. possessing), possessing spinules on only 5 anal-fin rays (vs. 7 or more), presence of a long dark pink horizontal marking on the caudal peduncle (vs. absence), five supraneurals (vs. four or fewer), and a yellow pelvic-fin filament (vs. pale rosy).

The species is included in this genus by virtue of possessing all diagnostic characters given in the description of N. venustus, and its discovery expands the range of the genus which was previously known only from the rio Jequitinhonha in Minas Gerais state.

For further information download the full, open access paper: Negreiros de Bragança, P. H., M. A. Barbosa and J. L. Mattos, 2013. A new Nematocharax species from the middle Contas River basin, Northeastern Brazil (Characiformes: Characidae). Vertebrate Zoology 63(1): 3-8