A new Caryospora coccidian species (Apicomplexa: Eimeriidae) from the laughing kookaburra (Dacelo novaeguineae)

• Description of a new Caryospora – like coccidian parasite in kookaburra.
• Morphological characterisation: most similar to Caryospora.
• Molecular characterisation at 18S and 28S rRNA loci: most close to Besnoitia.

A new Caryospora coccidian species is described from the laughing kookaburra (Dacelo novaeguineae). Sporulated oocysts (n = 30) are ovoid in shape with a smooth, colourless, bilayered oocyst wall and measure 31.4 × 29.3 (30.0–32.0 × 28.0–31.0) μm with a shape index of 1.1. Oocysts contain one spheroidal to subspheroidal sporocyst, 21.2 × 20.6 (20.0–24.0 × 20.0–21.0) μm. A spheroidal shaped sporocyst residuum is present; micropyle, Stieda, substieda and parastieda bodies are absent. Vermiform sporozoites (n = 8) are arranged either parallel or randomly in the sporocyst, measuring 17.0 × 4.8 (16.0–18.0 × 4.0–6.0) μm, with a L/W ratio of 3.5. There is a large spheroidal, posterior refractile body in the middle of the sporozoite. Morphologically, this new species is most similar to Caryospora. The prevalence of this parasite was 6.7% in birds sampled in the morning and 33.3% from those sampled after midday. Further molecular characterisation was conducted at two loci; the 18S and 28S ribosomal RNA (rRNA). At the 18S locus, the new species of Caryospora was most closely related to Besnoitia besnoiti (99.2% similarity) and Hammondia triffittae (98.8% similarity). Although, no 28S partial sequences from Caryospora were available in GenBank, the highest similarity was with B.besnoiti (91.3%). Based on morphological and molecular data, this coccidian parasite is a new species that to date has not been reported. The new coccidian parasite is named Caryospora daceloe n. sp. after its host D.novaeguineae (the laughing kookaburra).

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