| Diversification, co-evolution, and historical biogeography of the rodent tapeworm Arostrilepis horrida: This ongoing research is part of the Beringian Coevolution Project (BCP), a NSF funded effort to systematically survey the mammals and associated parasites of the Beringian region, which spans eastern Siberia and northwestern North America. During glacial periods, sea levels dropped hundreds of feet to expose the Bering Land Bridge, which formed a crossroads for biotic interchange between the northern continents. A goal of the BCP is to develop a model for understanding the biodiversity, evolution, and historical biogeography of northern faunas. In collaboration with the PIs of the BCP, Eric Hoberg (curator of the US National Parasite Collection) and Joseph Cook (curator of mammals at the Museum of Southwestern Biology), I am characterizing a cryptic species complex of rodent tapeworms (Arostrilepis horrida sensu lato) and exploring its diversification within the context of its hosts' biogeographic histories. Arostrilepis horrida was formerly considered to be a single widespread and morphologically variable host-generalist that was found in association with most arvicoline rodents. Our molecular analyses demonstrate that, in fact, A. horrida represents a complex of at least 10 reciprocally monophyletic and host-specific lineages. We are examining the mode of diversification within this complex (e.g., did parasite lineages "co-speciate" with their hosts or did host-switching play a role in speciation?) and exploring its implications for a general biogeographic framework for northern faunas. | ||
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