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United States Department of Agriculture

Agricultural Research Service

Title: Hamulonema Gen. Nov. for Ostertagia Kenyensis and Teladorsagia Hamata in the Ostertagiine Fauna (Nematoda: Trichostrongyloidea) from African Ungulates

Authors
item Hoberg, Eric
item Abrams, Arthur

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 3, 2007
Publication Date: August 29, 2008
Citation: Hoberg, E.P., Abrams, A. 2008. Hamulonema gen. nov. for ostertagia kenyensis and teladorsagia hamata in the ostertagiine fauna (nematoda: trichostrongyloidea) from african ungulates. Journal of Parasitology. 94:866-879.

Interpretive Summary: The medium stomach worms, often referred to the subfamily of ostretagiine nematodes remain among the most significant pathogens of ungulates throughout the world. Although this group of roundworms has received considerable attention in studies of taxonomy, systematics, and distribution, our knowledge of diversity in the group remains incomplete. Such is significant because continued translocation of host animals and parasites through globalization serves to introduce parasites into new host species and new geographic settings. Our continuing studies of the diversity in this significant nematode group have revealed a previously unrecognized genus, and provide new insights about these parasites. We now propose Hamulonema gen. nov. for two species in the ostertagiine fauna- Teladorsagia hamata and Ostertagia kenyensis found in ungulate hosts (antelopes) from Africa. Monomorphic species representing this genus are characterized by unique patterns of ridges on the body surface and a suite of other structural attributes. Species of Hamulonema are among those exotic nematodes that may be introduced into North America. Our research provides the capacity for relatively rapid and definitive identification of these potential pathogens

Technical Abstract: : Hamulonema gen. nov. is proposed for Teladorsagia hamata and Ostertagia kenyensis in the ostertagiine nematode fauna found in artiodactyl hosts from Africa. Monomorphic species representing this genus are characterized by a bilaterally symmetrical and parallel synlophe in males and females, a 2-2-1 bursal formula, an accessory bursal membrane which is strongly cuticularized and reduced, a strongly reduced dorsal lobe and ray, and robust spicules with a simple, weakly pointed, ventral process, and curved, hook-like dorsal process. Species referred to Hamulonema nov. gen. are immediately distinguished from species of Camelostrongylus, Longistrongylus, Marshallagia, Orloffia, Ostertagia and Pseudomarshallagia by the structure of the 2-2-1 bursa in males. Hamulonema nov. gen. is distinguished from those genera having a 2-2-1 bursa, including Africanastrongylus, Cervicaprastrongylus, Hyostrongylus, Mazamastrongylus, Sarwaria, Spiculopteragia, and Teladorsagia by the structure of the synlophe, bursa, genital cone, “0” and “7” papillae, dorsal lobe and spicules in specific instances. In the global fauna 4 of 14 ostertagiine genera are endemic to Africa. African genera may represent morphologically divergent and discrete or historically isolated lineages reflecting a pattern of geographic and host colonization as a driver for diversification since the Miocene.

Last Modified: 4/19/2014