Sarcocystis hippopotami sp. n. and S-africana sp. n. (Protozoa, Sarcocystidae) from the hippopotamus (Artiodactyla, Hippopotamidae) in South Africa

Two new Sarcocystis species found in muscle fibres of the diaphragm of a hippopotamus in South Africa are described by light and electron microscopy. Sarcocystis hippopotami sp. n. forms macrocysts (4-10 x 0.66-1.10 mm) with a parasite-induced encapsulation of the host muscle fibre in which the plasma membrane of the latter remains unaltered. The sarcocyst wall represents a new ultrastructural type, characterized by thumb-like villar protrusions with a compact central bundle of microtubules in the core. The bradyzoites (15.6 x 2.2 mu m) are straight and slender. Sarcocystis africana sp. n. forms round microcysts (diameter 0.5-0.7 mm) representing a new type of the cyst wall ultrastructure which is characterized by irregularly semicircular or rectangular villar protrusions with granular and fibrillar content. The bradyzoites (9.5 x 3.1 mu m) are straight and plump.