A novel Eimeria species found in the marbled polecat (Vormela peregusna)

There are no known coccidian parasites reported from the marbled polecat ( Vormela peregusna ; IUCN Vulnerable), a mustelid found in southeastern Europe and western Asia. There are eleven Eimeria species documented in other mustelids. This study reports a complete mitochondrial genome (mtDNA) from Eimeria species found in marbled polecat. Intestinal samples from seven nature-killed or road-killed individuals (collected 2020 - 2023 in Xinjiang, China) were subjected to genomic DNA extraction. cox1 nested PCR screening revealed Eimeria infection in 3/7 hosts. Full mitochondrial genome amplification using five overlapping primer pairs yielded a 6,179 bp sequence (GenBank PV393175). This mtDNA exhibits classic apicomplexan features: three protein-coding genes ( cytb , cox1 and cox3 ), fragmented rRNAs, and no tRNAs. The mtDNA shows high A+T bias (64.49%). Phylogenetically, Eimeria isolate in marbled polecat was clustered with Eimeria mephitidis (bootstrap=100%) yet displayed significant mitogenomic divergence (only 97.65% sequence identity), particularly in cox3 (95.11% vs. intraspecific minimum identity 95.50%). Combined with mtDNA arrangement, significant genetic divergence and host association, we characterized a novel mitochondrial genome from an Eimeria species. • Reports the first Eimeria sp. from the vulnerable marbled polecat ( Vormela peregusna ). • The mitogenome has a unique, uniformly oriented gene arrangement. • Significant genetic divergence supports a distinct species hypothesis. • Distinct host family (Mustelidae vs. Mephitidae) provides ecological evidence. • Proposed as “ Eimeria sp. Vormela” under modern DNA-based taxonomy frameworks.