A New Host for (Apicomplexa: Eimeriidae) from the Eastern Hognose Snake, (Ophidia: Colubroidea: Dipsadinae), from Arkansas, U.S.A., with a Summary of Hosts of This Coccidian.

Between May 2012 and July 2013, four eastern hognose snakes () were collected from Arkansas ( = 2) and Oklahoma ( = 2), U.S.A., and examined for coccidians. A single from Arkansas was found to be passing oocysts of Anderson, Duszynski, and Marquardt. Oocysts of were spheroidal to slightly subspheroidal with a rough, colourless, bi-layered wall, measure 23.5 × 22.8 µm, and have a length/width (L/W) ratio of 1.0; both micropyle and oocyst residuum were absent, but a prominent polar granule was present. Sporocysts are ovoidal, 16.8 × 12.8 µm, L/W 1.3; a prominent Stieda and subStieda body was present; a sporocyst residuum was present and composed of numerous spheroidal granules dispersed into small and large granules. Sporozoites lie lengthwise and parallel in a semi-spiral in sporocyst; a spheroidal anterior refractile and posterior refractile body is present; a single nucleus is located between the 2 refractile bodies. This represents the first report of a caryosporan reported from as well as the only known coccidian from this host. A summary of hosts of is provided.