Integrating morphology and DNA barcoding to assess cetacean diversity in Brazil

Stranded cetaceans (whales, dolphins, and porpoises) are frequently used to obtain data on species occurrence demographic trends. Accurate species-level identification of these individuals is crucial, but often challenging or impossible when relying solely morphological features (e.g., for highly decayed specimens). To aid in the development a reliable molecular assay cetacean DNA-based identification, we tested efficacy standardized DNA barcode segment coxI gene identifying occurring off Brazilian coast its continental waters. We generated sequences from 150 specimens (collected by 16 institutions), most which included voucher material (skulls, skeletons and/or images) deposited scientific collections. This allowed direct comparison between their identification. CoxI correctly identified ~93% samples, comprising 33 (70% 47 reported waters). Two (Berardius arnuxii Phocoena dioptrica) were sequenced first time. For only two dolphins (Stenella coeruleoalba S. clymene) right whale (Eubalaena australis), failed identify due overlapping distributions intra- vs. interspecific divergences. Only one occurs southern hemisphere, facilitating this case. Stenella present extensive sympatry potential inter-species hybridization, suggesting that nuclear markers may be required These results indicate barcoding can reliably stranded highlight importance materials validate construction system.