Molecular characterization and reference mitogenome of the hookworm <i>Uncinaria criniformis</i> (Goeze, 1782) from the Eurasian badger

Hookworms are common parasites of Eurasian badgers (<i>Meles meles</i>), typically identified as <i>Uncinaria criniformis</i>. The taxonomic distinction from <i>Uncinaria stenocephala</i>, a species found in dogs and foxes, has long been debated. In this study, we molecularly characterized <i>U. criniformis</i> from a Eurasian badger in Romania using genome skimming. We assembled the complete mitochondrial genome and internal transcribed spacer (ITS) rDNA region from 2 adult hookworms morphologically consistent with <i>U. criniformis</i>. Phylogenetic analysis of 12 mitochondrial protein-coding genes demonstrated strongly supported clade of <i>U. criniformis</i> with <i>Ancylostoma</i> spp. ITS rDNA and <i>cox</i>1 sequence comparisons revealed only 92.4-92.8% and 88.0-88.5% identity, respectively, between <i>U. criniformis</i> and <i>U. stenocephala</i>, confirming their molecular distinctiveness. In contrast, our sequences showed >99% identity to sequences from <i>Arthrostoma leucurus</i>, a hookworm recently described from the Asian badger (<i>Meles leucurus</i>), suggesting conspecificity. These findings support the validity of <i>U. criniformis</i> as a distinct species parasitizing <i>M. meles</i>, and we propose <i>A. leucurus</i> as a junior synonym of <i>U. criniformis</i>. Our results highlight the polyphyly of the genus <i>Uncinaria</i> and point to the need for broader mitogenomic sampling of hookworms. The molecular markers generated here provide a reference for future parasitological surveys and wildlife disease studies.