Reevaluation of RAPD markers involved in a case of stingray misidentification (Dasyatidae: Dasyatis).

We investigated a reported case of stingray Dasyatis americana misidentification not detected in a published study using the random amplified polymorphic DNA (RAPD) technique. If the referred specimen (landed by fisheries in Ceará, northeastern Brazil) was misidentified (as Dasyatis centroura) in the field, why did its RAPD data fail to clarify the mistake? Was it due to limitations of RAPD markers or perhaps to a taxonomic issue? Contrary to our initial expectations, neither of these hindered the detection of the misidentification. After reanalyzing the primary genetic data associated with the misidentified specimen (PCR gel photographs and/or matrices of presence/absence of markers for six RAPD primers), we found that the RAPD markers were sufficient to correctly assign the misidentified specimen to its proper species identity. In the original study, the specimen misidentification was neither noticed by the authors nor apparent in the published article due to how their results were interpreted and presented.