A redescription of Cylicocyclus adersi Boulenger, 1920 (Nematoda: Strongyloidea: Cyathostominae) parasitic in equids.

As part of a revision of the systematics of the Cyathostominea of equids, we determined that the single type-specimen of Cylicocyclus adersi Boulenger, 1920 is missing and a modern description of this rare species parasitic in donkeys Equus asinus L. and zebras E. burchelli (Gray) and E. zebra L. is not available. Systematists at a workshop on the systematics of the Cyathostominea of horses, convened on August 11, 1997 in Sun City, South Africa, listed C. adersi as a species inquirenda . Herein, we provide a redescription of C. adersi and propose a neotype for the species. The distinctive shape of the buccal capsule of C. adersi , with a relatively tiny 'hoop-like thickening' at its base, a relatively small oesophageal funnel with a thick cuticular lining, and a short, but distinct, dorsal gutter readily distinguishes this species from other large species of Cylicocyclus Ihle, 1922.