title: DNA barcoding identifies Argentine fishes from marine and brackish waters.
abstract: BACKGROUND
  DNA barcoding has been advanced as a promising tool to aid species identification and discovery through the use of short, standardized gene targets. Despite extensive taxonomic studies, for a variety of reasons the identification of fishes can be problematic, even for experts. DNA barcoding is proving to be a useful tool in this context. However, its broad application is impeded by the need to construct a comprehensive reference sequence library for all fish species. Here, we make a regional contribution to this grand challenge by calibrating the species discrimination efficiency of barcoding among 125 Argentine fish species, representing nearly one third of the known fauna, and examine the utility of these data to address several key taxonomic uncertainties pertaining to species in this region.
  
  
  RESULTS
  Specimens were collected and morphologically identified during crusies conducted between 2005 and 2008. The standard BARCODE fragment of COI was amplified and bi-directionally sequenced from 577 specimens (mean of 5 specimens/species), and all specimens and sequence data were archived and interrogated using analytical tools available on the Barcode of Life Data System (BOLD; www.barcodinglife.org). Nearly all species exhibited discrete clusters of closely related haplogroups which permitted the discrimination of 95% of the species (i.e. 119/125) examined while cases of shared haplotypes were detected among just three species-pairs. Notably, barcoding aided the identification of a new species of skate, Dipturus argentinensis, permitted the recognition of Genypterus brasiliensis as a valid species and questions the generic assignment of Paralichthys isosceles.
  
  
  CONCLUSIONS
  This study constitutes a significant contribution to the global barcode reference sequence library for fishes and demonstrates the utility of barcoding for regional species identification. As an independent assessment of alpha taxonomy, barcodes provide robust support for most morphologically based taxon concepts and also highlight key areas of taxonomic uncertainty worthy of reappraisal.
authors.affiliation: Laboratorio de Biotaxonomía Morfológica y Molecular de Peces, Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Marinas y Costeras, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. emabraga@mdp.edu.ar
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Mabragaña
authors.forename: Juan Martín
authors.initials: JM
authors.lastname: Díaz de Astarloa
authors.forename: Robert
authors.initials: R
authors.lastname: Hanner
authors.forename: Junbin
authors.initials: J
authors.lastname: Zhang
authors.forename: Mariano
authors.initials: M
authors.lastname: González Castro
mesh_terms: D000818:Animals; D001118:Argentina; D058893:DNA Barcoding, Taxonomic / Q000379:methods*; D003576:Electron Transport Complex IV / Q000235:genetics; D005399:Fishes / Q000145:classification* / Q000235:genetics*; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D010802:Phylogeny; D012492:Salts; D012623:Seawater
chemical_list: D012492:Salts; C017082:brine; D003576:Electron Transport Complex IV