Molecular and morphological evidence flag a likely new cryptic species within the Neotropical genus Salminus (Actinopterygii: Characidae)

ROSSO, JUAN JOSE; MABRAGAÑA, EZEQUIEL; GONZÁLEZ CASTRO, MARIANO; DÍAZ DE ASTARLOA, JUAN MARTÍN

Yeosu

Conferencia; FISH-BOL 2012. Fish Barcode of Life World Conference; 2012

The fish species of the genus Salminus are mid- to large predatory animals often placed at the top of the food webs in most of the large rivers of South America. They all represent highly valuable fishery resources, particularly for sport fishing. In spite of the great popularity and economical importance, the taxonomical knowledge of the genus is still unsatisfactory. There are 4 formally described species, Salminus brasiliensis, S. franciscanus, S. hilarii and S. affinis. For this presentation, four specimens of Salminus brasiliensis captured at the southernmost extreme of its distribution range were analysed. Both molecular and morphological evidence suggest that a new cryptic species of this genus could inhabit freshwater ecosystems of the Pampa Plain, Argentina. At a first glance, traditional taxonomical approach using morphometric and meristic characters revealed few differences among samples and suggested co-specificity. However, genetic differences among them were rather high. Interestingly, 3 specimens which differed from more than 6% from the fourth specimen, displayed a number of scales in the lateral line (LL: 101, 101 and 102) that ?lays? at the extreme of the wide range reported for the species (79-102). Moreover, these Salminus also showed lower snout/SL and upper jaw/SL ratios. These 3 ?conflictive? specimens also showed a genetic distance larger than 5% when compared with the remaining species of the genus using the species database in BOLD. Conversely, the fourth specimen (95 scales in LL with larger snout/SL and upper jaw/SL ratios), perfectly matched the cluster of Salminus brasiliensis. We have not found available COI sequences to contrast our findings with Salminus affinis. Nevertheless, morphological and meristic analyses of our samples easily discriminated them from S. franciscanus, S. hilarii and S. affinis.