Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2007
Publication Date: February 29, 2008
Citation: Hoberg, E.P., Abrams, A., Ezenwa, V.O. 2008. An exploration of diversity among the Ostertagiinae: Africanastrongylus buceros GEN. NOV. ET SP. NOV. (Nematoda: Trichostrongyloidea) in African Buffalo (Syncerus caffer). Journal of Parasitology. 94:230-251. Interpretive Summary: Invasive and exotic species or parasites constitute a continuing threat to diversity and to efficient production for both domestic and wild ungulates throughout the world. Systematics, taxonomy and baseline data for biodiversity are the foundations for documenting, understanding and predicting the outcomes of introductions of novel species into new ecosystems and the exposure of previously naïve host groups. We report on the discovery and identification of a new genus and species of abomasal nematode in Cape buffalo from Uganada, Kenya and South Africa, and outline the current knowledge for diversity of the African fauna. An understanding of the history and structure of parasite faunas in artiodactyls becomes increasingly important in defining the potential for translocation and establishment, geographic and host colonization, and patterns of emergence for disease. Baseline data are essential in formulating predictions about responses of complex host-parasite systems to ecological perturbation and climate change over time. Biodiversity baselines are important in establishing a framework to document introductions and dissemination. Africanastrongylus buceros a new genus and species represents yet another nematode with the potential for successful translocation with infected ungulate hosts. Introduction and establishment of helminths with otherwise tropical histories and adaptations like species of Haemonchus or A. buceros may have eventual consequences linked to the cascading effects of habitat change driven by global warming.
Technical Abstract: Abomasal nematodes (Ostertagiine: Trichostrongyloidea) representing a previously unrecognized genus and species are reported in African Buffalo (Syncerus caffer caffer) from Kenya, Uganda and South Africa. Africanastrongylus buceros gen. nov. et sp. nov. is characterized by a symmetrical tapering synlophe in the cervical region and a maximum of 60 ridges in males and females. Bursal structure is 2-2-1, with subequal Rays 4/5, massive Rays 8 and Rays 9/10, and a massive dorsal lobe which is reduced in length, laterally and dorsally inflated, and positioned ventral to externo-dorsal rays. Spicules are tripartite, and the gubernaculum is broadly alate in the anterior. A proconus is present. Among ostertagiines with a 2-2-1 bursa (Cervicaprastrongylus, Hyostrongylus, Mazamastrongylus, Sarwaria, Spiculopteragia, and Teladorsagia) specimens of Africanastrongylus are differentiated from respective genera based on the structure of the cervical synlophe, patterns of dorsal, externodorsal, lateral and ventral rays, and configuration of the genital cone, gubernaculum, and spicules. Among 12 genera of the Ostertagiinae in the global fauna, 3 are entirely limited in distribution to Africa, including Africanastrongylus, Longistrongylus and Pseudomarshallagia. Another 5 genera including Cervicaprastrongylus Hyostrongylus, Marshallagia, Ostertagia and Teladorsagia are represented as mosaics, with diversity centered in Eurasia or the Holarctic. Genera not represented in the African fauna include Camelostrongylus among Caprinae and some Antelopinae, Mazamastrongylus and Spiculopteragia in Cervidae from Eurasia and the Nearctic and Sarwaria among Tragulidae and Bovinae in southern Asia. The diverse nature of the ostertagiine fauna, with a disproportionate number of endemic genera relative to other regions of the Northern Hemisphere, may reflect the timing of episodic expansion events for artiodactyls into Africa from Eurasia during the Tertiary and Quaternary.