The third newly discovered Eimeria species (Protozoa: Eimeriidae) described from wild reindeer, Rangifer tarandus, in Iceland.

Fecal samples from 56 adult reindeer from eastern Iceland were examined for coccidian parasites. One Eimeria species was found in an 8-year-old male. Prevalence of infection was 1.8%; oocyst per gram (opg) value was 150. The coccidium was identified and described as a new species. The sporulated oocysts are ellipsoidal and average size is 30.0 x 21.1 microm. The oocyst has two distinct walls. Wall thickness is approximately 1.0 microm, and the outer wall, approximately four-fifths of total thickness, is generally smooth and appears bicoloured. The outermost portion is light blue, and the innermost portion, yellow to pale brown. The inner wall is dark brown. Oocysts contain a prominent polar granule but are devoid of a micropyle. Oocysts enclose four spindle-shaped sporocysts with a rounded end opposite to the Stieda body. The average size of sporocysts is 15.3 x 6.5 microm. Sporocysts contain a granular sporocyst residuum that usually forms a cluster between the sporozoites and one large refractile body in each sporozoite.