Two Brazilian scientists have described a new species of rivulid killifish from the Rio Tocatins system in central Brazil.
Wilson Costa and Gilberto Brasil of the Federal University of Rio de Janeiro described the new species Simpsonichthys radiosus in the ichthyological systematics journal Zootaxa.
Simpsonichthys radiosus forms a clade that the scientists have named the Simpsonichthys notatus group, which includes S. notatus, S. radiosus, S. stellatus, S. rufus, S. trilineatus and S. occelatus, all of which share a unique pattern of scales on their chests.
Brasil and Costa say that S. radiosus differs from other Simpsonichthys due to the colour of its tail fin, and its wider basihyal.
The paper includes a key to identifying the members of the newly erected S. notatus group.
The species is one of several rivulids described by Costa this year.
For more details read the paper: Costa, WJEM and G. Brasil (2004) - Simpsonichthys radiosus sp. nov. (Teleostei: Cypriniformes: Rivulidae): a new annual killifish from the Rio Tocatins, central Brazil. Zootaxa, 737: 1-7.