Hosts: Sheep, Rocky Mountain bighorn sheep.
Location: Unknown. Oocysts found in feces.
Geographic Distribution: North America, Europe (Germany).
Prevalence: This species is relatively uncommon in sheep. Christensen (1938a) found in in 10% of 100 sheep from Maryland and New York. Jacob (1943) found it in 1% of 100 sheep in Germany. Honess (1942) remarked that it was more frequent and numerous in bighorn sheep than in domestic sheep in Wyoming.
Morphology: This species has been described by Christensen (1938a). The oocysts are piriform or shaped like a stout, broad-shouldered urn, with the micropyle and micropylar cap at the broad end; small oocysts are often bluntly ellipsoidal. The oocysts are 22 to 35 by 17 to 25 u with a mean of 29.4 by 20.9 u. Their length-width ratio is 1.2 to 1.7 with a mean of 1.41. The micropyle is distinct, 3 to 5 u in diameter. The micropylar cap is prominent, 5 to 10 u wide and 1 to 2.5 u high with a mean of 7.5 by 1.7 u; it is shaped like a broad truncated cone with a flat or slightly convex top, and is easily dislodged. The oocyst wall is transparent, pale brownish-yellow to yellowish-brown, and composed of 2 layers, the outer one being transparent, pale yellow to yellowish-green, and half as thick as the inner, heavier layer. The oocyst wall is lined by a membrane. An oocyst polar granule and oocyst residuum are absent. The sporocysts are ovoid, with a sporocyst residuum. The sporozoites have a retractile globule at each end. The sporulation time is 8 to 4 days.
Life Cycle: Unknown.