Sarcocystis inghami n. sp. (Sporozoa: Sarcocystidae) from the skeletal muscles of the Virginia opossum Didelphis virginiana in Michigan

This report describes the newly identified Sarcocystis inghami n. sp. from the skeletal muscles of opossums (Mammalia: Didelphidae) that were collected from south central Michigan (42° 43′-42° 79′N, 84° 18′-84°mathtype="display">6'W), USA. The new species is distinguished from all species described from North and South American opossums by the distinctive morphology of the villar protrusions on the cyst wall. Sarcocysts of S. inghami are microscopic, up to 700 μm long and 110 μm wide. The sarcocyst wall is up to 7 μm thick, with long, stalked protrusions which average 5.5 × 1.2 μm. These are constricted at the base, expanded laterally, rounded off distally and occasionally bifid. The villar protrusions have numerous microtubules without electron−dense bodies that extend from the tips into the granular layer. Bradyzoites are 10.7 × 4.3 (8−−12 × 4−−5) μm. This is the second species of Sarcocystis sarcocyst described from the Virginia opossum in North America.