ABSTRACT
The oocysts of Eimeria falconensis sp. n. is described from the feces of the lanner falcon, Falco biarmicus, from the falcon market in Riyadh city, Saudi Arabia. Sporulated oocysts are ellipsoid in shape, measuring 27.2x18.1 [25.4-29.5x 16.3-20.4] micro m; shape index [length/width ratio] is 1.5 [1.35-1.68 micro m. The oocyst wall is smooth and bi-layered. Mmicropyle and polar granule are present, but an oocyst residuum is absent. Sporocysts are ellipsoid, 11.0 x6.9 [10.1-12.6 x 5.8-7.9] micro m; with shape index of 1.59 [1.43-1.68] micro m, with a smooth single-layered wall and a prominent Stieda body, but there is no substieda body. The sporocyst residuum consists of numerous small granules. Sporozoites are comma-shaped, each contains two refractile bodies