Eimeria collieie n. sp. (Apicomplexa:Eimeriidae) from the western long-necked turtle (Chelodina colliei)

Abstract

A new species, Eimeria collieie n. sp., is described from the western long-necked turtle (Chelodina colliei). Sporulated oocysts (n = 35) are spherical to subspherical, with colourless single layer oocyst wall, 0.6 ± 0.2 (0.4–0.7) µm thick. Oocyst with elongated ellipsoid sporocysts. Oocyst length, 29.8 ± 0.4 (28.2–31.0) µm; oocyst width, 29.4 ± 0.3 (28.0–30.8) µm; oocyst length/width (L/W) ratio, 1.0 ± 0.03 (1.0–1.05). Micropyle, oocyst residuum and polar granule were absent. Sporocysts with sporocyst residuum and 2 sporozoites. Sporocyst length, 21.6 ± 0.4 (21.2–22.0) µm; sporocyst width, 6.0 ± 0.3 (5.7–6.3) µm; sporocyst L/W ratio, 3.6 ± 0.2 (3.4–3.8). Stieda, parastieda and substieda bodies were absent. Sporozoite length, 14.0 ± 0.2 (13.8–14.2) µm; sporozoite width, 2.6 ± 0.2 (2.4–2.8) µm; sporozoite L/W ratio, 5.46 ± 0.10 (5.4–5.6). Molecular analysis was conducted at three loci: the 18S and 28S ribosomal RNA (rRNA), and the mitochondrial cytochrome oxidase gene (COI). At the 18S rRNA locus, E. collieie n. sp. shared 96.4% and 98.3% genetic similarity to E. ranae (GenBank accession number: EU717219) and E. arnyi (AY613853) respectively. At the 28S rRNA locus, E. collieie n. sp. shared 91.6% genetic similarity to E. papillata (GenBank accession number: GU593706) and phylogenetic analysis at this locus placed E. collieie n. sp. in aseparateclade. At the COI locus, E. collieie n. sp. shared 92.7% genetic similarity to Eimeria setonicis (GenBankaccession number: KF225638) from a quokka (Setonix brachyurus) in Western Australia. Reptile-derived sequences were not available for the 28S rRNA and the COI loci. Based on morphological and molecular data, this isolate is a new species of coccidian parasite that, to date, has only been found in western long-necked turtles.