Eimeria tiliquae n. sp. (Apicomplexa: Eimeriidae) from the shingleback skink (Tiliqua rugosa rugosa).

Abstract

A new species, Eimeria tiliquae n. sp. is described from a shingleback skink (Tiliqua rugosa rugosa). Sporulated oocysts (n=50) are spherical to subspherical, with colourless trilaminate oocyst wall, 0.7±0.1 (0.5-0.75) thick. Oocyst with 4 spheroidal to subspheroidal sporocysts. Oocyst length, 13.7±0.9 (12.0-16.3); oocyst width, 12.8±0.9 (11.5-15.0); oocyst length/width (L/W) ratio, 1.07±0.05 (1.0-1.2). Micropyle, oocyst residuum and polar granule absent. Sporocysts with globular sporocyst residuum and 2 sporozoites. Sporocyst length, 6.0±0.6 (5.0-7.5); sporocyst width, 5.4±0.6 (4.0-7.0); sporocyst L/W ratio, 1.11±0.11 (1.0-1.5). Stieda, parastieda and substieda bodies absent. Phylogenetic analysis of 18S rRNA sequences indicated that E. tiliquae n. sp. shared 96.4-96.5% genetic similarity to E. tropidura, its closest relative. Reptile-derived sequences were not available for the mitochondrial cytochrome oxidase gene (COI) and phylogenetic analysis at this locus placed E. tiliquae n. sp. in a clade by itself but grouping closest (92% similarity) with a novel isolate from a King's skink (Egernia kingii) from Western Australia. Based on morphological and molecular data, this isolate is a new species of coccidian parasite that to date has only been found in shingleback skinks.