Umingmakstrongylus pallikuukensis gen.nov. et sp.nov. (Nematoda: Protostrongylidae) from muskoxen, Ovibos moschatus, in the central Canadian Arctic, with comments on biology and biogeography

Abstract

Umingmakstrongylus pallikuukensis gen.nov. et sp.nov. is established for a protostrongylid nematode in muskoxen, Ovibos moschatus, from the Kitikmeot Region (central Arctic) of the Northwest Territories, Canada. It is distinguished from Cystocaulus and other Muelleriinae by characters that include the following: males: deeply incised, bilobed bursa, independent externodorsal rays, telamon composed of distal transverse plate, absence of falcate crurae, and spicules not distally split; females: absence of provagina; and first-stage larvae: presence of three cuticular folds on the tail. The great length of females (468 mm) and males (171 mm) is exceptional among the Protostrongylidae. Pathognomonic lesions include well-defined cysts dispersed through the lung tissue (maximum diameter 40 mm) containing adult and larval parasites in a dense matrix. Transmission involves a molluscan intermediate host, as indicated by experimental infections in the slug Deroceras reticulatum. The parasite is apparently restricted in its geographic distribution and has been found only in a population of muskoxen northwest of Coppermine, N.W.T. This may be indicative of a relictual host–parasite assemblage that has existed since the Pleistocene. The pathogenicity, high prevalence, and intensity of infection in the Coppermine herd suggest that the occurrence of U. pallikuukensis has implications for the management of muskoxen in the Holarctic region.