Integrated Taxonomy Revealed Genetic Differences in Morphologically Similar and Non-Sympatric Scoliodon macrorhynchos and S. laticaudus

Previous examination of the mitochondrial gene and morphological characteristics led to the resurrection of as a second valid species in the genus, in addition to . This study applied an integrated taxonomic approach to revisit the classification of the genus based on new materials from the Malaysian Peninsula, Malaysian Borneo and Eastern Bay of Bengal. Mitochondrial DNA data suggested the possibility of three species of in the Indo-West Pacific, while the nuclear DNA data showed partially concordant results with a monophyletic clade of and paraphyletic clades of and cf. from the Malacca Strait. Morphological, meristic and dental characteristics overlapped between the three putative species. Collective molecular and morphological evidence suggested that the differences that exist among the non-sympatric species of are consistent with isolation by distance, and remains as a valid species, while cf. is assigned as . The Malacca Strait acts as a spatial delineator in separating the Pacific (including South China Sea) from the Northern Indian Ocean . Future taxonomic work should focus on clarifying the taxonomic status of from the Indonesian waters.