Isospora phainopepla n. sp. (Apicomplexa: Eimeriidae) from Phainopepla nitens (Swainson) (Passeriformes: Ptiliogonatidae) in the Joshua Tree National Park, USA.

Isospora phainopepla n. sp. is described from the faeces of Phainopepla nitens (Swainson) collected in Joshua Tree National Park, California, USA. To our knowledge, there are no metazoan or protist parasites described yet from any species in the Ptiliogonatidae of the Americas. Sporulated oöcysts of the isosporan are ellipsoidal, 30-35 × 22-29 (32.9 × 25.4) μm, with a length/width (L/W) ratio 1.20-1.35 (1.30); one rice-shaped polar granule is present, but both oöcyst residuum and micropyle are absent. Sporocyts are elongate-ellipsoidal, 22-27 × 11-14 (23.9 × 12.0) μm, with L/W ratio 1.97-2.02 (2.00); prominent Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent. Sporocyst residuum of many scattered granules is present and the sporozoites have prominent anterior and posterior refractile bodies. This parasite is clearly new to science and represents the first species of Isospora hosted by a New World bird species from this small family of silky flycatchers (Ptiliogonatidae). This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as 7F664B0D-DF0E-4CAD-8CEA-45D79C8BBF92. This article was published as an Online First article on the online publication date shown on this page. The article should be cited by using the doi number. This is the Version of Record.