DNA barcoding of Smiliogastrinae (Teleostei: Cypriniformes) of Bangladesh based on cytochrome c oxidase subunit I (COI) sequences

This study aims to molecularly characterize the phylogenetic relationship of small barbs under the Subfamily Smiliogastrinae (Cypriniformes: Cyprinidae) in Bangladesh using a fragment of the mitochondrial gene cytochrome c oxidase subunit I (COI). Samples were collected from rivers, haors (a seasonal wetland), baors (an oxbow lake), beels (perennial waterbody), and floodplains. A total of eleven species under five genera were confirmed based on both morphological and molecular approaches. The average Kimura two-parameter (K2P) distances for intraspecies and interspecies were 0.0058 and 0.1538, respectively. The mean GC content was markedly low (44.03%) in the COI sequences of the smiliogastrin species compared to the mean AT content (55.97%). In addition to the barcode-based species identification, phylogenetic relationships among the species were also explored. Phylogenetic (neighbor-joining, parsimony, and maximum likelihood) as well as species delimitation (ASAP and mPTP) analyses of all the eleven species revealed distinct clusters in concurrence with the taxonomic status of the species.