Isospora juruviarae n. sp. (Apicomplexa: Eimeriidae) from chivi vireos Vireo chivi (Vieillot, 1817) (Passeriformes: Vireonidae) in South America.

Chivi vireos Vireo chivi (Vieillot, 1817) are passerine birds widely distributed throughout Brazil, but mainly observed in the Atlantic Forest of the South and Southeast regions of the country. In this context, the current study identifies a new species of Isospora Schneider, 1881 from V. chivi captured in the Marambaia Island, on the coast of the State of Rio de Janeiro, Southeastern Brazil. The oocysts of Isospora juruviarae Andrade & Berto n. sp. are subspheroidal to ovoidal, measuring on average 26 by 24 μm. Micropyle is absent or inconspicuous. Oocyst residuum absent, but polar granules are present. Sporocysts are ellipsoidal with pointed posterior end, measuring on average 17 by × 11 μm. Stieda and Sub-Stieda bodies are present. Sporocyst residuum is present among the vermiform sporozoites, which have refractile bodies and nucleus. This morphology was different from the other Isospora spp. recorded in the same family, superfamily and parvorder as the host. Molecular identification was targeted by the amplification and sequencing of two different loci of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and one locus of the 18S small subunit ribosomal RNA (18S) gene. Phylogenetic analyses were not very efficient in forming monophyletic groups associated with host taxon, zoogeographical region or taxonomic character; however, they confirmed the identification as a new species through comparison with sequences from Isospora spp. of wild passerines. Finally, based on the morphological and molecular analyses of the oocysts recovered from the chivi vireo V. chivi in the current work, I. juruviarae is considered new to science, being the second species recorded in the host family Vireonidae and the first to have a supplementation by molecular identification.