EN
Paranoplocephala kalelai (Tenora, Haukisalmi et Henttonen, 1985) is an anoplocephalid cestode that primarily parasitizes the grey-sided vole Myodes rufocanus (syn. Clethrionomys rufocanus) in northern Fennoscandia. In a preliminary molecular phylogenetic analysis, the cytochrome oxidase I (mtDNA) sequences of P. kalelai formed two divergent sublineages originating from two different localities in northern Finland and northern Norway. The present data confirm the existence of two strongly supported clades and show that their geographic distributions are overlapping in northernmost Finland. Relatively deep genetic divergence and coexistence of the two main clades at one of the localities suggest that the material may include two biological species. However, because the specimens representing the two mtDNA clades of P. kalelai are not morphometrically sufficiently differentiated and because the mtDNA clade of the specimens from the type locality is unknown, they are not assigned to different species. Comparison with the existing phylogeographic data of M. rufocanus suggests that the genetic structure of this host-specific cestode reflects the glacial and post-glacial history of its primary host. A redescription is presented for P. kalelai.