RESEARCH ARTICLE Identification, Discrimination, and Discovery of Species of Marine Planktonic Ostracods Using DNA Barcodes

The Ostracoda (Crustacea; Class Ostracoda) is a diverse, frequently abundant, and ecolog-ically important component of the marine zooplankton assemblage. There are more than 200 described species of marine planktonic ostracods, many of which (especially conspe-cific species) can be identified only by microscopic examination and dissection of fragile morphological characters. Given the complexity of species identification and increasing lack of expert taxonomists, DNA barcodes (short DNA sequences for species discrimination and identification) are particularly useful and necessary. Results are reported from analysis of 210 specimens of 78 species of marine planktonic ostracods, including two novel spe-cies, and 51 species for which barcodes have not been previously published. Specimens were collected during 2006 to 2008 from the Atlantic, Indian, and Southern Oceans, Green-land Sea and Gulf of Alaska. Samples were collected from surface to 5,000 m using various collection devices. DNA sequence variation was analyzed for a 598 base-pair region of the mitochondrial cytochrome oxidase subunit I (COI) gene. Kimura-2-Parameter (K2P) genetic distances within described species (mean = 0.010 ± 0.017 SD) were significantly smalle