Phylogeography and trematode parasitism of Oreohelix land snails in southern Alberta

Abstract

Modern studies in phylogeography integrate many once-disparate scientific fields. This study investigated terrestrial mountain snails, Oreohelix spp., in southern Alberta using DNA markers and the recent emergence of the trematode parasite Dicrocoelium dendriticum. Large-bodied snails in Cypress Hills (CH) and the Rocky Mountains (RM) formed three clades within the species complex O. subrudis. One was geographically widespread, one was restricted to one region in the RM, and one was restricted to CH. Small-bodied snails in CH were determined to be O. cooperi, a rare Oreohelid thought to be imperilled in the western U.S.A. Phylogeographic analyses determined that snails likely colonized and came into contact in CH due to its glacial history. There was significant spatial and seasonal variation in the prevalence of D. dendtriticum in all three lineages of Oreohelix present in CH. Isolation and geological history have played an important role in determining Oreohelid biogeographical patterns in this region.