Identification and genetic characterization of a novel species of Choleoeimeria Schneider, 1875 from a captive‐bred bilby (Thylacomyidae; Macrotis lagotis) (Reid, 1837) in Western Australia

Abstract

A novel Eimeria sp. from a captive‐bred bilby ( Macrotis lagotis Reid, 1837) has been identified in Western Australia. The bilby was bred at the Kanyana Wildlife Rehabilitation Centre, Perth, as part of the National Bilby Recovery Plan. Oocysts ( n = 31) irregular blunt ellipsoidal, 17–18 × 11–12 (17.2 × 11.3); length/width (L/W) ratio 1.4–1.5 (1.5). Wall bi‐layered, 0.8–1.0 (0.9) thick, outer layer smooth, c.2/3 of total thickness. Micropyle barely discernible. Oocyst residuum is absent, but 2–3 small polar granules are present. Sporocysts ( n = 31) ovoidal, 7–8 × 5–6 (7.8 × 5.7); L/W ratio 1.3–1.4 (1.4). Stieda, sub‐Stieda and para‐Stieda bodies absent or indiscernible; sporocyst residuum present, usually as an irregular body consisting of numerous granules that appear to be membrane‐bound or sometimes diffuse among sporozoites. Sporozoites vermiform with a robust refractile body. Further molecular characterization was conducted on the sporulated oocysts. At the 18S locus, it sat in a large clade of the phylogenetic tree with two isolates of Eimeria angustus from quendas ( Isoodon obesulus Shaw, 1797) and the Choleoeimeria spp. It shared the highest identity with E. angustus (KU248093) at 98.84%; at the COI gene locus, it was unique and most closely related to Choleoeimeria taggarti, which is hosted by another species of marsupial, the yellow‐footed antechinus ( Antechinus flavipes flavipes), with 90.58% genetic similarity. Based on morphological and molecular data, this isolate is a new species and named as Choleoeimeria yangi n. sp.

Abstract

A new species of Choleoeimeria from a captive‐bred bilby ( Macrotis lagotis Reid, 1837) has been identified and described using morphological and molecular information.