Molecular and statistical approaches to the delimitation of Eimeriidae species: a case of extreme polymorphism in eimerian oocysts from the plumbeous pigeon Patagioenas plumbea (Vieillot, 1818) (Columbiformes) in South America.

The current work aimed to analyze, morphologically, statistically, and molecularly, oocysts shed from plumbeous pigeons, Patagioenas plumbea (Vieillot, 1818), from a locality at 2197 m of altitude near the Agulhas Negras peak, the highest point of the State of Rio de Janeiro, southeastern Brazil. The oocysts were extremely polymorphic, being subspheroidal, ovoidal, or ellipsoidal, in addition to having the random presence/absence of characteristic features associated with the oocyst wall, such as micropyle, micropyle cap, lateral micropyle, and outer veil/rough wall. Linear regression confirmed the extreme polymorphism of oocysts, showing that if all combinations of taxonomic characters in oocysts (morphotypes) were overestimated, 19 different species could be identified/described. In contrast, the means comparison analysis between oocysts with the presence/absence of characteristic features and the histograms showed equivalences and regularity in the distribution in the classes of measures, which indicate the presence of a single species in the measured oocysts. Molecular analyses were performed from the isolation of individual oocysts of different morphotypes, which had their genetic material extracted, amplified, and sequenced in 4 non-overlapping loci in the cox1 and cox3 genes and fragments of the small and large subunit rDNA of mitochondrial DNA. The sequences were 100% identical between the morphotypes, with the exception of a very small divergence observed at the locus that partially covers the cox3 gene. The phylogenetic analysis was inconclusive for the locus within the cox1 gene traditionally used for eimeriid coccidians; however, the other loci should have a promising future for phylogenetic studies when more sequences for the same genic regions are deposited in GenBank. Finally, the multifactorial analysis of the current work supported that the polymorphic oocysts shed from P. plumbea are a single species, which was named Eimeria patagioenasae, making this the twenty-second eimerian description from Columbiformes.

Distribution, redescription, and molecular identification of Isospora striata McQuistion et al. 1997 (Eimeriidae), from woodcreepers (Dendrocolaptidae) in South America.

Woodcreepers are passerines of the family Dendrocolaptidae, which have a high forest dependency. The current work aimed to redescribe Isospora striata McQuistion et al. 1997, from two new hosts in protected areas in Brazil, revealing new localities of parasitism, in addition to providing preliminary genotypic identifications via sequencing of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene from both host species. Isospora striata has oocysts that are subspheroidal to ovoidal, 19.4 × 16.8 µm with smooth wall. Oocyst residuum is absent, but micropyle and polar granules are present. Sporocysts are ovoidal, 13.6 × 8.3 µm, with both Stieda and sub-Stieda bodies. Sporocyst residuum is present and sporozoites with refractile body, nucleus, and striations. The morphological study and the 100% similarity in sequencing of the COI gene between samples of different dendrocolaptid species confirmed the identification of a single species, supporting the identification of I. striata in the Brazilian Atlantic forest and consequently the wide distribution of this coccidian species in the Neotropical Region.