Abstract
The oocysts of Caryospora cherrughi sp. n. were described from the feces of the saker falcon, Falco cherrug, collected from the falcon market in Riyadh City, Saudi Arabia. The prevalence of infection was 21.4 % (15/70). The majority of the oocysts examined had completed sporulation within 64-84 h at 24 ± 2 °C. Sporulated oocysts are ovoid in shape, measuring 32.1 × 29.3 (30.7-34.5 × 27.7-29.8) μm; shape index (L/W) is 1.1 (1.04-1.27) μm. The oocyst wall is smooth and bilayered. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ellipsoidal, measuring 24.1 × 19.6 (23.0-25.5 × 18.7-20.5) μm; with a smooth single-layered wall, but there is no Stieda body. The sporocyst residuum is present as numerous small granules. Sporozoites are banana-shaped, blunt at one end, and slightly tapered at the other, each with a large single refractile body. C. cherrughi sp. n. is the third caryosporian species described from F. cherrug.