Varestrongylus eleguneniensis sp. n. (Nematoda: Protostrongylidae): a widespread, multi-host lungworm of wild North American ungulates, with an emended diagnosis for the genus and explorations of biogeography

Authors: VEROCAI, GUILLHERME - University Of Calgary; KUTZ, SUSAN - University Of Calgary; SIMARD, MANON - Makivik Corporation; Hoberg, Eric

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2014
Publication Date: 2/1/2015
Publication URL: http://DOI 10.1186/s13071-014-0556-9
Citation: Verocai, G.G., Kutz, S.J., Simard, M., Hoberg, E.P. 2014. Varestrongylus eleguneniensis sp. n. (Nematoda: Protostrongylidae): a widespread, multi-host lungworm of wild North American ungulates, with an emended diagnosis for the genus and explorations of biogeography. Parasites & Vectors. 7:556.

Interpretive Summary: Molecular prospecting involving extensive geographic coverage and intensive sampling of free-ranging ungulates revealed the occurrence of an unknown lung nematode at boreal to high latitudes. Initially known only from collections of larval parasites, new field surveys led to recovery of adult worms in muskoxen and caribou, and provided the basis to characterize this nematode in detail. Varestrongylus eleguneniensis sp. n. is established and described for a recently discovered protostrongylid nematode found in caribou (Rangifer tarandus), muskoxen (Ovibos moschatus) and moose (Alces americanus), hosts that collectively occupy a broad geographic range across northern North America. Biogeographic history for V. eleguneniensis and V. alpenae, the only two endemic species of Varestrongylus known from North America, appears consistent with independent events of geographic expansion with cervid hosts from Eurasia into North America during the late Pliocene and Quaternary. Significance of the study resides in examination of the climatological factors that have controlled distribution and evolution of the complex parasite faunas in ungulates, serving as a model to anticipate and predict the cascading influence of accelerating climate change across wild and managed ecosystems. Further, results documented are a powerful validation of integrated approaches in systematics and taxonomy relying on explorations of structural and molecular characters in defining species limits and patterns of diversity. Applications by parasitologists, wildlife biologists, disease ecologists and modelers of climate related processes are apparent in understanding the influence of dynamic environments contributing to patterns of parasite faunal diversity.

Technical Abstract: Varestrongylus eleguneniensis sp. n. is established for a recently discovered protostrongylid nematode found in caribou (Rangifer tarandus), muskoxen (Ovibos moschatus) and moose (Alces americanus), hosts that collectively occupy an extensive geographic range across northern North America. Descriptions are based on mature adult specimens in the terminal bronchioles of muskoxen from Quebec, and a woodland caribou from central Alberta, Canada. Adults of Varestrongylus eleguneniensis are distinguished from congeners by a combination of characters in males (distally bifurcate gubernaculum, relatively short equal spicules not split distally, a strongly elongate and bifurcate dorsal ray, and an undivided copulatory bursa) and females (reduced provagina with hood-like fold extending ventrally across prominent genital protuberance). Third-stage larvae, recovered from experimentally infected slugs (Deroceras reticulatum), resemble those found among other species in the genus. The genus Varestrongylus is emended to account for the structure of the dorsal ray characteristic of V. eleguneniensis, V. alpenae V. alces and V. longispiculatus. Biogeographic history for V. eleguneniensis and V. alpenae, the only two endemic species of Varestrongylus known from North America, appears consistent with independent events of geographic expansion with cervid hosts from Eurasia into North America during the late Pliocene and Quaternary.