Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 23, 2011
Publication Date: N/A
Interpretive Summary: Climate change and ecological perturbation are modifying the host and geographic distributions of pathogenic nematodes which circulate in domestic and free ranging ungulates in North America and globally. This situation heightens the need to provide accurate identification of these parasites. In the current study we conducted field collections and examined museum-based resources to explore the identity and diversity of nematode faunas in northern ungulates. These studies revealed the occurrence of a previously unrecognized form of the nematode Teladorsagia boreoarcticus which circulates primarily at high latitudes in free ranging ungulates. Recognition of this new morphotype contributes to baselines to understand the current patterns of distribution of hosts and parasites, particularly in instances involving borderlands between wild and managed systems.
Collections to explore helminth diversity among free-ranging ungulates in the North American Arctic revealed the occurrence of a third male, or “davtiani,” morphotype for Teladorsagia boreoarcticus. Designated as T. boreoarcticus foma (f.) minor B, these males occurred with T. boreoarcticus f. major and T. borearcticus f. minor A in endemic populations of muskoxen (O. m. wardi) and barrenground caribou (R. tarandus groenlandicus) on Victoria Island, Nunavut, Canada and in muskoxen and Peary caribou (R. tarandus pearyi) on Banks Island, NWT. These specimens differ from conspecific morphotypes in the structure of the genital cone and Sjoberg’s organ. Relative to T. boreoarcticus f. minor A, specimens of T. boreoarcticus f. minor B are consistently smaller and mean dimensions for the bursa, and spicules do not overlap. The robust spicules are similar in form, particularly in the relative length of the dorsal and ventral processes, but mean total length is substantially less in specimens of T. boreoarcticus f. minor B. Differences that distinguish the minor morphotypes of T. boreoarcticus parallel those demonstrated for the T. trifurcata and T. davtiani morphotypes in association with T. circumcincta sensu stricto. Aspects of nomenclature for polymorphic ostertagiines are explored. Host records and species limits for Teladorsagia spp. at high latitudes in North America are examined.