Marin, A.; Zavalaga, F.; Gozzer-Wuest, R.; Santos-Rojas, L. E.; Reyes-Flores, L. E.; Alfaro, R.; Bearez, P.; Zelada-Mazmela, E.

Hypanus brevis (Garman, 1880) and H. dipterurus (Jordan & Gilbert, 1880) are currently considered as a conspecific lineage of the "diamond stingray" from the Eastern Pacific. This taxonomic group has been the subject of nomenclatural disputes for about 145 years. To clarify the historical confusion surrounding this lineage, we employed an integrative taxonomic approach using specimens from the Eastern North and Eastern South Pacific (ENP and ESP). The genetic results, based on single and multilocus mitochondrial analyses, revealed a distinct evolutionary unit in the ESP. While morphological analyses detected subtle differences between ENP and ESP specimens, most characters exhibited significant overlap (e.g., disc shape, dentition patterns, body coloration), suggesting low evolutionary divergence. A calibrated molecular clock analysis estimated this divergence at approximately 3.09 Ma. In accordance with Garman's (1880) original description based on specimens from Paita (northern Peru), we formally resurrect H. brevis from synonymy with H. dipterurus. Our findings suggest an anti-tropical speciation pathway, with core populations of H. brevis and H. dipterurus restricted to the temperate waters of the ESP and ENP, respectively. Notably, a single, fixed COI haplotype was detected in all H. brevis specimens from the north-central Peruvian coast. This result may indicate a severe bottleneck event, raising concerns about the genetic health and long-term viability of this vulnerable species. Finally, we analyzed historical fishery data of H. brevis to infer its current population status, suggesting targeted conservation measures and precautionary management to prevent further loss of genetic diversity.