DNA Barcoding reveals taxonomic conflicts between Sardinella aurita and S. brasiliensis.

MABRAGAÑA, EZEQUIEL; DELPIANI, SERGIO MATIAS; GONZÁLEZ CASTRO, MARIANO; ROSSO, JUAN JOSE; BLASINA, GABRIELA; DÍAZ DE ASTARLOA, JUAN MARTÍN

Adelaide

Conferencia; 4th International Barcode of Life Conference; 2011

As part of a general study on DNA barcoding of Argentine fishes, two clupeids of the genus Sardinella were first caught in Mar Chiquita coastal lagoon (MCH) in December 2008. MCH is a temperate shallow coastal lagoon located in Buenos Aires province, Argentina (37º32?-37º45?S 57º19?-57º26?W). The fish fauna of MCH is composed approximately by 28 species, including three clupeids: Brevoortia aurea (Spix and Agassiz), Platanichthys platana (Regan) and Ramnogaster arcuata (Jenyns). Two species of Sardinella occur in the southwest Atlantic: Sardinella aurita Valenciennes and S. brasiliensis (Steindachner), but only the former was occasionally reported on Argentine waters. Morphometric, pair and unpair fins rays, and anterior rakers on lower limbs were recorded. Standard DNA barcoding protocols were followed for molecular analysis. Sequence divergences were calculated using K2P. Unrooted NJ tree of available sequences of species of Sardinella in BOLD (Barcode of Life Data System) were build using MEGA 4.1. For ?not public? sequences the NJ tree were created using BOLD. Morphometric and meristic characters matched with that of S. aurita. A 652 base pair amplicon for the COI gene was bidirectionally sequenced (GenBank Accession numbers: HM421919 and HM421920). The individuals differed by two nucleotides. Considering public and non-public records in BOLD, the specimens analyzed matched with Sardinella aurita in 98.82 to 100% and with S. janeiro (junior synonym of S. brasiliensis), in 99.16 to 100%. Both specimens are clustered together with specimens of S aurita and S. janeiro and formed a different cluster from that of other congeners. The taxonomic status of the genus in the West Atlantic Ocean is unclear. Although difference on gill raker counts would separate both species, some authors regarded this feature as low diagnostic value at species level. Results from DNA Barcoding support those obtained with other molecular markers, suggesting S. aurita and S. brasiliensis are conspecific