Integration of DNA barcodes with truss-network morphology for taxonomic validation and stock differentiation of Heteropneustes fossilis

The stinging catfish Heteropneustes fossilis is a commercially and ecologically important freshwater species, yet information on its taxonomic status, population structure, and genetic diversity remains limited. This study conducted an integrated assessment combining morphometric, meristic, truss-network, and molecular analyses to evaluate the population quality of three geographically distinct stocks collected from Head Trimmu, Head Taunsa, and Chashma Barrage. Twenty-seven morphometric, six meristic and twenty truss variables were measured. Total length of H. fossilis varied from ۱۲۶.۱۰- ۲۸۳.۰۶ mm. Among six meristic characters, only PecFS showed no variation, while the remaining five traits exhibited significant differences in population. Significant morphometric traits included TL, SL, HBD, LBD, HL, HD, PrOL, PsOL, MXBL, MNBL, PrDL, PsDL, PrPevL, PrAnL, HPec, HPev, HAF, LAFB, CFL, and IO (p< ۰.۰۵), whereas SnL, ED, PrPecL, HDF, LDFB, LPevFB, and LPecFB were non-significant (p>۰.۰۵). Truss variables data showed significant difference (p<۰.۰۵). Principal component analysis of morphometric data revealed that the first four components (PC۱–PC۴) explained ۷۷.۷%, ۸.۷%, ۳.۷%, and ۲.۹% of total variance, respectively, while PCA of meristic traits accounted for ۹۲.۶% of variation. In truss analysis of H. fossilis, the loading proportion of the initial four elements from principal components; PC۱, PC۲, PC۳ and PC۴ defined ۲۰.۸%, ۴.۹%, ۴.۱% and ۱.۰% of the change, respectively. DNA barcoding was conducted on five representative samples. Sequence analysis revealed moderate AT-bias (A+T=۵۸%) and highest GC content (۴۲%) at the first codon position. Inter-population K۲-P distances ranged from ۰.۰۰۰۰ to ۰.۰۱۰۲, indicating minor divergence among populations likely due to geographical and environmental influences. BLAST analysis confirmed ۱۰۰% similarity with reference sequences, validating species-level identification. Phylogenetic analyses using Maximum Likelihood trees showed all H. fossilis sequences clustering into a cohesive clade with low divergence, confirming the reliability of CO۱ as a DNA barcode. Overall, this study provides an integrated morphological and molecular characterization of H. fossilis populations in Pakistan, validates DNA barcodes for the species, and establishes a foundational framework for future studies on biodiversity assessment, stock discrimination, and conservation management of threatened freshwater catfishes in the region.

کلیدواژه ها:

Heteropneustes fossilis ، Taxonomic Identification ، Genetic Analysis ، Truss Variables ، Principal Components Analysis ، Conservation ، Management