A new species of giant tetra in the genus Salminus has been described from eastern and northeastern Brazil.
Publishing their results in the latest issue of the journal Neotropical Ichthyology, Flvio Lima and Heraldo Britski have named the tetra Salminus franciscanus, after the Sa Francisco, the river drainage to which the new species is endemic.
The new species can be distinguished from other members of the genus except for S. brasiliensis in having the second dentary tooth in the outer tooth series considerably larger than the remaining teeth.
It differs from S. brasiliensis in having much lower scale counts in the lateral line series, the horizontal between the dorsal-fin origin and the lateral line, and the horizontal between the lateral line and pelvic-fin insertion.
Like many other members of the Characidae, Salminus franciscanus is sexually dimorphic, with mature males having hooks on the pelvic and anal fins.
The presence of the new species in the Sa Francisco River drainage has been recorded for more than a hundred years, but it was always incorrectly identified, most frequently as S. brasiliensis (or its junior synonym, S. cuvieri).
Salminus franciscanus is one of the largest known characiform fish, reaching up to a metre in total length and weights of up to 30 kg.
It is a piscivorous species that undertakes reproductive migrations during the rainy season.
For more information, see the paper: Lima, FCT & HA Britski (2007) Salminus franciscanus, a new species from the rio Sa Francisco basin, Brazil (Ostariophysi: Characiformes: Characidae). Neotropical Ichthyology 5: 237"244.