Echis carinatus (Serpentes: Viperidae) as a new host for Caryospora maxima (Apicomplexa: Eimeriidae) in Saudi Arabia.

Caryospora maxima is redescribed from the intestinal contents of the viperid snake, Echis carinatus collected from Gazan area in the southern region of Saudi Arabia. This report represents a new host and geographic location for the parasite. Sporulated oocysts of this coccidian are spherical to subspherical, 42.8 x 41.2 (40.3-45.9 x 39.6-43.8) microm, with smooth brownish-yellow bilayered wall, 1.9 (1.5-2.3) microm. thick. Micropyle and oocyst residuum are absent. Some oocysts had a small polar granule. Sporocysts are broadly ellipsoid, 22.1 x 16.8 (21.0-23.3 x 15.5-17.4) microm., with a prominent stieda and substieda bodies. Sporocyst residuum is present consisting of many granules in compact mass. Sporozoites are banana-shaped, each with two refractile globules. Oocyst measurements were similar to those reported from Psammophis schokari in Jordan. Except for the presence of a spherical polar granule, the oocyst morphology was identical to the original description of C. maxima.