ABSTRACT
The genus Caryospora Leger, 1904 is currently the third most speciose of the Eimeriidae. About 40 members are assigned to the genus at present, most of which occur in snakes and raptors. Until the early 1980s, all species of Caryospora were considered monoxenous, with merogony, gamogony, and formation of oocysts occurring in the intestine. Early researchers studied the life cycle of C. simplex in the intestinal tract of Vipera aspis which supported the hypothesis. Caryospora spp. from snakes generally represent either one of two basic morphologic types, based predominantly on features of the oocyst wall. All lack a micropyle and oocyst residuum and have sporocysts with a Stieda body. Most species of Caryospora infecting avian hosts occur in raptors. With a few exceptions, oocysts are generally large, spherical to ovoid, lack a micropyle and oocyst residuum, and have a simple spherical or subspherical sporocyst that lacks a Stieda body and encloses eight stubby sporozoites and a residuum.
