Morphological and Molecular Characterization of a New (Apicomplexa: Eimeriidae) Species From a Singing Honeyeater ( Vieillot, 1817) (Passeriformes: Meliphagidae) in Western Australia.

We describe and characterize a new species from the Singing honeyeater () in Western Australia, both morphologically and molecularly. Microscopic analysis of a fecal sample identified 25 ellipsoidal oocysts, measuring 21-25 × 18-20 μm (mean 23.4 × 18.7 μm), with a length/width (L/W) ratio of 1.2-1.3 (mean 1.25). The oocyst wall is bilayered and 1.0 μm thick, with a smooth outer layer making up about two-thirds of the thickness. A micropyle cap, measuring ~2.0 × 4.5 μm, is present as a curved protrusion on the outer layer. The micropyle itself is ~4.5 μm wide. The oocysts lack a residuum but contain 1-2 polar granules. The 25 ellipsoidal sporocysts measured 14-15 × 8-9 μm (mean 14.1 × 8.7 μm) with an L/W ratio of 1.6-1.7 (mean 1.62). The Stieda body is flattened (0.5 × 1.5 μm), the sub-Stieda body is rounded (~1.5 × 2.5 μm), and the para-Stieda body is absent. The sporocyst residuum, composed of clustered spherules, is ~3.5 × 3.5 μm. Sporozoites contain anterior and posterior refractile bodies and a nucleus. Molecular analysis of the 18S rRNA, 28S rRNA, and COI gene loci showed a 99.5% genetic similarity to at the 18S rRNA locus and 99.2% and 97.7% similarities to at the 28S rRNA and COI loci, respectively. Phylogenetic analysis confirmed that the new species is closely related to . Based on these data, we propose this isolate as a new species, n. sp.