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ARS Home » Research » Publications at this Location » Publication #73939
Title: A REDESCRIPTION OF CYLICOCYCLUS TRIRAMOSUS (NEMATODA: STRONGYLOIDEA): A PARASITE OF THE ZEBRA, EQUUS BURCHELLI

Author
item KHARCHENKO, V - INST ZOOLOGY, UKRAINE
item DVOJNOS, GRIGORI - INST ZOOLOGY, UKRAINE
item KRECEK, R - UNIV PRETORIA, SO AFRICA
item Lichtenfels, James

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Strongyloid nematodes are a major cause of morbidity and mortality in equines in the United States. Resistance to antiparasitic drugs (currently the only means of controlling the nematode disease in horses) is common and alternative control methods for these parasites are needed to protect horses in the United States. Considerable research is underway worldwide to develop improved control strategies. This research requires the identification of the more than 40 nematode species that are parasitic in the large intestine and caecum of horses. This report provides new information on one of the putative species of the genus Cylicocyclus, type specimens of which were lost. The results will be used by researchers worldwide working to control these economically important nematodes.

Technical Abstract: Cylicocyclus triramosus, a rare species of Cyathostominae from the Southern African zebra (Equus burchelli) is redescribed and a Neotype is proposed. The external leaf-crown (ELC) of the species consists of 30 elements and internal leaf-crown (ILC) of numerous small and clear elements. The buccal capsule is cylindrical, oval in cross section, and approximately 3 times as wide as deep. The thin walls of the buccal capsule taper anteriorly from a large ring-like, hoop-shaped thickening around the posterior margin. The dorsal gutter is nipple-shaped. The mouth collar is notched dorsally and ventrally. The dorsal ray of the copulatory bursa is slightly elongate and distinctly set off from the lateral lobes. The branches of the dorsal ray have auxiliary branches. Appendages of the genital cone consist of 2 separated, large, semilunar plates with finger-shaped processes on the margins. The tail of the female is short and straight and the vulva-to-anus distance is greater than the tail length. The species is most similar to Cylicocyclus radiatus. Cylicocyclus triramosus differs from all similar species in the presence of dorsal and ventral notches in its mouth collar. Cylicocyclus radiatus differs further from C. triramosus gutter, has a more elongate dorsal ray and a female tail nearly equal in length to the vulva to anus distance.