Background: The gnateaters Conopophaga spp. are insectivorous passerines commonly observed in high and humid forests, where they remain lodged in thin branches and, sometimes, they fly to the ground to catch insects. The insectivorous feeding habit is related to low prevalence and density of coccidians in passerines; however, several coccidian species are recorded for families of insectivorous passerines.
Purpose: This study aimed to examine the feces from gnateaters Conopophaga spp. captured in the municipality of Barra Mansa and in the Itatiaia National Park, State of Rio de Janeiro, Southeastern Brazil, to determine what coccidian parasites were present.
Methods: Nine gnateaters were captured with mist nets. Coccidian oocysts were recovered from the fecal samples by flotation in Sheather's saturated solution. Morphological observations, line drawings, photomicrographs and measurements were made in optical microscopy and digitally edited. The molecular analysis included the study of the sequence of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, with phylogenetic reconstructions based on the neighbor-joining and maximum likelihood analysis.
Results: Four Conopophaga spp. were positive for oocysts. An Isospora sp. considered as new to science is described and identified from Conopophaga melanops (Vieillot, 1818) and Conopophaga lineata (Wied, 1831). Isospora borbai n. sp. has oocysts that are subspheroidal, 17-22 × 15-22 (20.2 × 19.1) µm, with rough, bilayered wall, c.1.7 μm thick. Micropyle present, but without micropyle cap. Oocyst residuum absent, but one or two polar granules are present. Sporocysts are ellipsoidal, 12-15 × 8-11 (14.1 × 9.1) µm. The Stieda body is knob-like to half-moon-shaped and sub-Stieda body is rounded. Sporocyst residuum is present, composed of scattered spherules of different sizes. Sporozoites are vermiform with refractile body and nucleus. Molecular analysis at the cox1 gene exhibited similarity greater than 99% with Isospora spp. isolates from other Neotropical passerine birds.
Conclusion: Based on the morphological and molecular features, I. borbai is considered as new to science and the first coccidian species recorded from Conopophagidae.
Keywords: Coccidia; Molecular biology; Morphology; Médio Paraíba Region; Neotropical birds; Oocysts; Parque Nacional do Itatiaia; Phylogeny; Taxonomy; Thamnophilida.