DNA barcoding of an endemic species Rasbora philippina (Günther, 1880) found in Lake Wood, Zamboanga del Sur, Philippines

Rasbora species are a diverse group of freshwater fishes in Southeast Asia whose morphological similarity often complicates species delimitation. In the Philippines, six to seven species are recognized, including the endemic Rasbora philippina, which contributes to freshwater food webs and supports subsistence fisheries in Mindanao. Species identification is quite challenging, as ambiguous forms are variably identified as R. philippina, Rasbora argyrotaenia everetti, or Rasbora sp., reflecting its previous placement within the morphologically variable R. argyrotaenia complex. To clarify its taxonomy, we generated the first mitochondrial cytochrome c oxidase subunit I (COI) DNA barcodes for R. philippina using specimens from Lake Wood, Mindanao. Phylogenetic analyses revealed that R. philippina forms a distinct clade, clearly separated from other Rasbora species, including those from the R. argyrotaenia complex. These results establish the first genetic reference for R. philippina, resolving taxonomic uncertainties and providing a baseline for accurate identification, biodiversity monitoring, and conservation.