Mitochondrial genome refinement and comparative phylogenetics of Parastrongyloides trichosuri (KNP strain; Nematoda: Strongyloididae) from South Africa

BACKGROUND Parastrongyloides trichosuri Mackerras, 1959 (Nematoda: Strongyloididae) is a facultatively parasitic nematode infecting the common brushtail possum. A previously reported mitochondrial genome (mitogenome) from a Kruger National Park (KNP) isolate (GenBank: NC_028620) is incomplete, lacking the nad3 gene and the noncoding region (NCR), limiting its utility for comparative and phylogenetic studies. OBJECTIVES This study aimed to reconstruct, annotate, and validate a complete mitogenome of P. trichosuri (KNP strain) to enhance genomic accuracy and phylogenetic resolution within Strongyloididae. METHODS Whole-genome sequencing data (SRA: ERS056619) were reanalysed. Missing genes, including tRNA-Glu and atp6, were manually curated using BLASTn searches against Rfam v15, while cox3 and nad3 were confirmed through transmembrane topology analysis. FINDINGS The reconstructed mitogenome was 13,809 bp long, comprising 12 protein-coding genes, 22 tRNAs, 2 rRNAs, and a 539-bp tandem-repeat NCR. Gene order and structure were consistent with other Strongyloididae mitogenomes. Phylogenetic analysis supported P. trichosuri as a distinct lineage within the family. The annotated sequence has been deposited in the Third Party Annotation database in GenBank (accession No. BK075097). MAIN CONCLUSIONS This improved mitogenome fills an existing genomic gaps and provides a reliable reference for future comparative, phylogenetic, and evolutionary studies of Strongyloididae.