Eimeria atricillae n. sp. (Apicomplexa: Eimeriidae) from the laughing gull Leucophaeus atricilla (Linnaeus) (Aves: Charadriiformes: Laridae) in Port Isabel, Texas.

A new coccidian species, Eimeria atricillae n. sp. (Apicomplexa: Eimeriidae) collected from the laughing gull Leucophaeus atricilla, is reported from Port Isabel, Texas, USA. Sporulated oöcysts of the new species are spherical to subspherical, 16.0-18.1 × 14.4-16.6 (17.1 × 15.4) µm, with a length/width (L/W) ratio of 1.0-1.1; polar granules are present, but micropyle and oöcyst residuum are absent. Sporocysts are ovoid, 9.1-9.7 × 6.1-7.1 (9.4 × 6.6) µm, with a L/W ratio of 1.3-1.5; Stieda body present, but sub-Stieda and para-Stieda bodies are absent; sporocyst residuum diffuse.

Isospora dipperia n. sp. (Apicomplexa: Eimeriidae) from the American dipper Cinclus mexicanus Swainson (Passeriformes: Cinclidae) in Yosemite National Park, USA.

Isospora dipperia n. sp. is described from the feces of the American dipper Cinclus mexicanus Swainson collected in Yosemite National Park, California, USA. Sporulated oöcysts of the new species are subespherical, 20-24 × 17-21 (20.9 × 18.7) µm, with a length/width (L/W) ratio of 1.0-1.1 (1.1); one polar granule is present, but micropyle is absent. Sporocyts are lemon-shaped, 14-16 × 8-11 (15.5 × 9.8) µm, with a L/W ratio of 1.6; 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. The mean dimensions (15.9 × 13.8 µm) of unsporulated oöcysts of I. cincli Gottschalk, 1972 from the white-throated dipper C. cinclus (L.) in Europe, appear to be considerably smaller than those in I. dipperia n. sp. Comparisons of Isospora dipperia n. sp. with two species of Isospora Schneider, 1881 described in the Americas from birds of the family Sturnidae, related to Cinclidae, revealed that the mean dimensions of the sporulated oöcysts in the new species are considerably smaller than those in I. graculai Bhatia, Chauhan, Arora & Agrawal, 1973 from Gracula religiosa (24.6 × 22.4 µm) and I. rothschildi Upton, Wilson, Norton & Greiner, 2001 from Leucopsar rothschildi (22.3 × 21.6 µm). The new species is the first species of Isospora recorded in a bird of the family Cinclidae in the New World.

Isospora toxostomai n. sp. (Apicomplexa: Eimeriidae) from the curved-billed thrasher Toxostoma curvirostre (Swainson) (Passeriformes: Mimidae) at the Central highlands of Mexico.

Isospora toxostomai n. sp. (Apicomplexa: Eimeriidae) is described based on material from the curved-billed thrasher Toxostoma curvirostre (Swainson) in the Central Highlands of Mexico. The new species possesses subspherical oöcysts, with a smooth, bi-layered wall. Sporulated oöcysts measure 22-25 × 21-24 (23.4 × 22.3) µm; length/width (L/W) ratio of 1.0-1.1 (1.1). Sporocysts are ellipsoidal, 15-17 × 10-11 (15.8 × 10.5); L/W ratio of 1.3-1.6 (1.5). Micropyle and oöcyst residuum are both absent, and a polar granule present (many fibrils). Mean dimensions of both sporulated oöcysts and sporocysts of I. toxostomai n. sp. appear to be considerably larger than those of Isospora mimusi Coelho, Berto, Neves, Oliveira Flausino & Lopes, 2011 from the tropical mockingbird Mimus gilvus (Vieilot) in Brazil. This is the second species of Isospora Schneider, 1881 infecting a host of the Mimidae in the Americas.

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.

Eimeria aegoliusia n. sp. (Sporozoa: Eimeriidae) from the northern saw-whet owl Aegolius acadicus (Gmelin) (Strigiformes: Strigidae) in Mexico.

A new coccidian species (Chromista: Sporozoa: Eimeriidae) collected from the northern saw-whet owl Aegolius acadicus (Gmelin) is reported from Mexico. Eimeria aegoliusia n. sp. has subspherical oöcysts, with smooth, bi-layered wall. Micropyle and oöcyst residuum are both absent and a polar granule is present. To date, eight species of Eimeria Schneider, 1875 have been described from strigiform birds. Mean dimensions of sporulated oöcysts (23.7 × 22.4 µm) and sporocysts (12.8 × 8.3 µm) appear to be considerably smaller than those from other Eimeria spp. with owl definitive hosts: E. atheni Chauhan & Jain, 1979; E. megabubonis Upton, Campbell, Weigel & McKown, 1990; E. spenotytoi Carini, 1939; E. strigis Kutzer, 1963; and E. varia Upton, Campbell, Weigel & McKown. Dimensions of these sporulated oöcysts appear to be larger than those in E. bemricki Averbeck, Cooney, Guarnera, Redig & Stromberg, 1998. The presence of polar granules and their number allowed differentiation from E. bubonis Cawthorn & Stockdale, 1981 and E. nycteae Volf, Koudela & Modry, 1999. This is the first description of an eimeriid coccidian infecting A. acadicus.