DNA barcoding of Canada's skates.

DNA-based identifications have been employed across broad taxonomic ranges and provide an especially useful tool in cases where external identification may be problematic. This study explored the utility of DNA barcoding in resolving skate species found in Atlantic Canadian waters. Most species were clearly resolved, expanding the utility for such identification on a taxonomically problematic group. Notably, one genus (Amblyraja) contained three of four species whose distributions do not overlap that could not be readily identified with this method. On the other hand, two common and partially sympatric species (Little and Winter skates) were readily identifiable. There were several instances of inconsistency between the voucher identification and the DNA sequence data. In some cases, these were at the intrageneric level among species acknowledged to be prone to misidentification. However, several instances of intergeneric discrepancies were also identified, suggesting either evidence of past introgressive hybridization or misidentification of vouchered specimens across broader taxonomic ranges. Such occurrences highlight the importance of retaining vouchered specimens for subsequent re-examination in the light of conflicting DNA evidence.