Type host: Lithobates sylvaticus (LeConte, 1825), Wood frog.

Other hosts: None reported to date.

Type locality: NORTH AMERICA: U.S.A.: Arkansas, Izard County, 6.0 kn SW of Melbourn, off State Highway 9.

Geographic distribution: NORTH AMERICA: U.S.A.: Arkansas.

Description of oocyst: Oocyst shape:ovoidal ; number of walls: 1; wall thickness: 0.5; wall characteristics: smooth; L x W: 21.9 x 14.3 ((20-24 x 13-15); L/W ratio: 1.5 (1-3-1.7); M: absent; OR: absent; PG: usually absent, but sometimes 1-3 fragments are attached to the outer wall of the sporocysts. Distinctive features of oocyst: very thin wall and fragments of debris (former PGs?) attached to outer wall of sporocysts.

Description of sporocysts and sporozoite: Sporocyst shape: ovoidal; L x W: 10.9 x 7.4 (10-11 x 7-8); L/W ratio: 1.5 (1.3-1.6); SB: present (?) as a slight thickening at one end of sporocyst; SSB: absent; PSB: absent; SR: present; SR characteristics: 3.6 x 1.6, consisting of ~25 large, coarse, scattered granules; SZ: elongate, 11.1 x 1.7 (10-12 x ~2) in situ, with 2 RBs--one anterior-central, spheroidal, ~1.1 wide and one posterior, subspheroidal to ovoidal, 2.9 x 1.6 (2-3 x 1.4-1.6); an indistinct N lies between the 2 RBs. Distinctive features of sporocysts: none.

Prevalence: 11 of 13 (85%).

Sporulation: Exogenous; complete within 5 d at 23ºC.

Prepatent and patent periods: Unknown.

Site of infection: Unknown; oocysts recovered from rectal contents.

Endogenous development: Unknown.

Materials deposited: Photosyntype of sporulated oocysts in USNPC (No. 84163). Symbiotype host deposited at ASUMZ (Cat. No. 19434).

Remarks: The host frogs and their oocysts were collected in February, 1994; this was the first ranid frog in the United States documented to harbor coccidia. This species can be easily distinguished from E. kermiti and E. algonquini described from L. sylvaticus in Ontario, Canada. Sporulated oocysts of E. kermiti are larger and have an OR and PG, and sporocysts with a distinct SB while those of E. algonquini are spheroidal, with very thin-walled sporocysts.