Abstract
Oocysts of Eimeria gnui sp. n. are described from the faeces of the white-tailed gnu, Connochaetes gnu from the Riyadh Zoo, Saudi Arabia. Sporulated oocysts are elongate-ellipsoid 43.5 x 26.3 (40-49 x 24-29) mu m, and posses finely pitted wall and bilayered, 2 (1.5-2.5) mu m; micropyle is present but a polar granule and oocyst residuum are absent. Sporocysts are elongate-ovoid, 18.7 x 9 (16-20 x 7.6-10) mu m, with a sporocyst residuum and Stieda body. Sporozoites are elongate, club shaped, and contain two prominent refractile bodies.