RESUMO
A new species of Coccidia (Protozoa: Apicomplexa: Eimeriidae) isolated from emus, Dromaius novaehollandiae, which was observed in Brazil is described and named. Oocysts of Isospora dromaii n. sp. are subspheroidal to ovoid in shape, measure 21.6 × 19.8 µm, and have a double and smooth wall thickness of approximately 1.4 µm. In this species, micropyle, oocyst residuum, and polar granules are absent. The sporocysts are slightly ovoid in shape and measure 13.7 × 10.0 µm. Nipple-like Stieda body and prominent sub-Stieda body are present. The sporocyst residuum is composed of small dispersed granules of varying sizes. The sporozoites are characterized by an oblong refractile body and one centrally located nucleus. This is the first description of isosporid coccidia infecting birds of the family Dromaiidae.