Sarcocystis sybillensis sp. nov. from the North American elk (Cervus elaphus)

Sarcocystis sybillensis sp. nov. (Protozoa, Sarcocystidae) is described as a heteroxenous coccidium, with the elk (Cervus elaphus) as the natural intermediate host and the dog (Canis familiaris) as the experimental definitive host. The sarcocysts are microscopic, compartmented, and thick walled (up to 8 μm) with filamentous protrusions. The bradyzoites are 10.6 × 3.3 μm and the metrocytes are 8.8 × 5.4 μm. Sporocysts in the intestine of the dog are 15.5 × 10.7 μm. The ultrastructure of S. sybillensis is compared with that of the thin-walled sarcocysts of S. wapiti.