Investigating taxonomy and speciation of Quinqueserialis (Digenea: Notocotylidae) parasites with an integrative taxonomic approach

Abstract

Estimates of parasite diversity are inaccurate due to unrecognized cryptic species and phenotypic plasticity. Integrative taxonomy (genetics, morphology, and host use) increases the clarity of species delineation, and improves knowledge of parasite biology. I used this approach to resolve taxonomic issues and test hypotheses of speciation in a genus of trematodes, Quinqueserialis. Specimens from throughout North America were field-collected and obtained from museums. No cryptic species were found, but host-induced phenotypic plasticity was confirmed in one Q. species. I confirmed two previously documented Q. species, and revised the life cycle of one to include three novel snail hosts. A new Q. species was also discovered in northern Canada. I found that the three species were influenced differently by host specificity and geographic isolation and that further sampling is needed to understand Quinqueserialis spp divergence. I illustrated the importance of resolving the species diversity of parasites before exploring their evolutionary ecology.