Cytauxzoon conepatus n. sp. (Piroplasmida: Theileriidae) infecting Conepatus semistriatus (Mephitidae) in Brazil.

The genus Cytauxzoon comprises apicomplexan hemoparasites primarily associated with domestic and wild felids, with occasional reports in non-felid carnivores. This study reports the first detection and molecular characterization of Cytauxzoon conepatus n. sp. infecting Conepatus semistriatus (Mephitidae), thereby expanding the known host range of the genus in South America. Two free-ranging, clinically healthy individuals were captured in the Cerrado biome of western Bahia, Brazil. Intraerythrocytic piroplasm forms consistent with Cytauxzoon spp. were observed in blood smears, and infection was confirmed by conventional PCR. Phylogenetic analyses based on nuclear (18S rRNA) and mitochondrial (cytochrome b and cytochrome c oxidase subunit I) genes consistently revealed a distinct and well-supported monophyletic species, clearly separated from Cytauxzoon brasiliensis, C. felis, and other described species. The 18S rRNA sequences showed high nucleotide identity with American Cytauxzoon species (99.3-99.4%) and low p-distance values (0.006-0.007), whereas comparisons with European and Asian species yielded substantially higher p-distances (≥0.030). Mitochondrial markers exhibited greater genetic divergence: cytb p-distance values ranged from 0.074 to 0.077 in comparisons with C. felis and from 0.082 to 0.084 with C. brasiliensis, while cox-1 analyses revealed p-distance values of approximately 0.087-0.091 relative to both species, with nucleotide identity consistently below 92%. The congruent signal obtained from nuclear and mitochondrial markers supports the recognition of Cytauxzoon conepatus n. sp. as an evolutionarily distinct species, potentially endemic to the Brazilian Cerrado. These findings suggest that Cytauxzoon diversity in Neotropical ecosystems has been substantially underestimated and emphasize the importance of expanding multilocus molecular surveys to include non-felid carnivores.