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

Abstract

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.