A new species of Eimeria Schneider, 1885 (Apicomplexa: Eimeriidae) from the eastern gray squirrel, Sciurus carolinensis (Rodentia: Sciuridae: Sciurinae: Sciurini) from Oklahoma, USA.

A new species of Eimeria Schneider, 1885 is described from an eastern gray squirrel (Sciurus carolinensis) from McCurtain County, Oklahoma, USA. Oöcysts of Eimeria lukfataensis n. sp. are ellipsoidal with a rough pitted bi-layered wall, measure 23.8 × 14.9 µm, and have a length/width (L/W) ratio of 1.6; a micropyle is absent but an oöcyst residuum and polar granule(s) are present. Sporocysts are ellipsoidal and measure 12.5 × 6.1 µm, L/W 2.0; Stieda and sub-Stieda bodies are present, but para-Stieda body is absent. The sporocyst residuum is composed of small indistinct granules along the edge or in the center of the sporocyst. This is the first species of coccidian reported from S. carolinensis from Oklahoma and only the fourth species from the sciurid tribe Sciurini with oöcysts possessing an oöcyst residuum.