Molecular characterization and reference mitogenome of the hookworm Uncinaria criniformis (Goeze, 1782) from the Eurasian badger.

Hookworms are common parasites of Eurasian badgers (Meles meles), typically identified as Uncinaria criniformis. The taxonomic distinction from Uncinaria stenocephala, a species found in dogs and foxes, has long been debated. In this study, we molecularly characterized U. criniformis 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 U. criniformis. Phylogenetic analysis of 12 mitochondrial protein-coding genes demonstrated strongly supported clade of U. criniformis with Ancylostoma spp. ITS rDNA and cox1 sequence comparisons revealed only 92.4-92.8% and 88.0-88.5% identity, respectively, between U. criniformis and U. stenocephala, confirming their molecular distinctiveness. In contrast, our sequences showed >99% identity to sequences from Arthrostoma leucurus, a hookworm recently described from the Asian badger (Meles leucurus), suggesting conspecificity. These findings support the validity of U. criniformis as a distinct species parasitizing M. meles, and we propose A. leucurus as a junior synonym of U. criniformis. Our results highlight the polyphyly of the genus Uncinaria 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.