Type host: Myotis ciliolabrum (Audubon and Bachman, 1942). Western small-footed myotis.

Other hosts:Myotis ymanensis H. ALlen, 1964, Yuma myotis.

Type locality: NORTH AMERICA: USA: New Mexico, Taos County, Pilar, Orilla Verde.

Geographic distribution: NORTH AMERICA: USA: California, New Mexico.

Description of oocyst: Oocyst shape: spheroidal to subspheroidal; number of walls: 2; wall thickness: <1.0; wall characteristics: both layers of approximate equal thickness; outer, yellowish, smooth; inner, dark, smooth; L x W: 15.0 x 14.1 (14-16 x 14-16); L/W ratio: 1.1 (1.0-1.2); M: absent; OR: absent; PG: 1. Distinctive features of oocyst: small size, smooth thin wall.

Description of sporocysts and sporozoites: Sporocyst shape: ovoidal; L x W: 7.1 x 5.9 (6-9 x 5-7); L/W ratio: 1.2 (1.1-1.5); SB: present, small; SSB: absent; PSB: absent; SR: present; SR characteristics: a singular refractile mass, ~2.0 or as disbursed granules obscuring SP; SP: with a spheroidal RB at posterior end. Distinctive features of sporocyst: small size, indistinct SB.

Prevalence: 1/12 (8%) in type host; 4/70 (6%) in M. yumanensis.

Sporulation: Presumably exogenous. Oocysts sporulated in 2% aqueous (w/v) potassium dichromate solution in the field.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. Oocysts recovered from feces.

Materials deposited: Symbiotype host, M. ciliolabrum, in the Museum of SW Biology, UNM: NK 32306, 22 June 1995. Photosyntypes in the USNPC no. 86938.

Remarks: Eimeria pilarensis is most similar to E. vejsovi and E. kunmingensis except that it is small than the former (15 x 14 vs. 21 x 18) and the latter has an inner wall that is wrinkled. Also, E. pilarensis, like E. rhynchonycteridis, differs from all other New World bat eimerians by having a smooth wall, but E. rhynchonycteridis is larger (25.5 in diameter) and has a thin wall with one obvious layer, whereas E. pilarensis is much smaller and has an oocyst wall with two layers.

References: Scott and Duszynski (1997).