A taxonomical re-evaluation ofsp. (Cestoda: Diphyllobothriidea) from Siberian cottid fishes (Russia).

Abstract

spp. are widely distributed Holarctic cestodes that comprise key model species for host-parasite studies.and, the most extensively studied species, exhibit narrow host specificity. Another species,, is known from the European bullhead (); however, information on its host range, geographical distribution, and molecular data remain poorly characterized. In Siberia, plerocercoids offound in sculpins were previously recorded from endemic cottid fishes of Lake Baikal and were identified as, which is inconsistent with the known host specificity of this species. The present study aims to clarify the species identity offrom Siberian cottid fishes using morphological and molecular data, and to test the hypothesis of conspecificity ofplerocercoids from sculpin hosts across Eurasia and North America. Morphologically, Siberian plerocercoids correspond to the description of, supporting their assignment to this species. The phylogenetic analysis confirmed the identity of the plerocercoids asand demonstrated the existence of two distinctlineages in North America and Siberia. These findings indicate that at least two differentspecies infect sculpins in the Old and New Worlds.