Isospora troglodytes n. sp. (Apicomplexa: Eimeriidae), a new coccidian species from wrens of Costa Rica

A New Isospora (Apicomplexa: Eimeriidae) from the Carolina Wren, Thryothorus ludovicianus ludovicianus (Passeriformes: Certhioidea: Troglodytidae), in Southeastern Oklahoma, USA

PURPOSE

Nothing is known of the coccidian parasites of the Carolina wren, Thryothorus ludovicianus ludovicianus (Latham, 1790). Here, we report a new species of Isospora from T. l. ludovicianus from Oklahoma, USA.

METHODS

Faecal samples were collected between September and December 2021 from five adult T. l. ludovicianus taken with a mist net from McCurtain County, Oklahoma, USA, and examined for coccidian parasites. Samples were placed in individual vials containing aqueous potassium dichromate. They were examined for coccidia after flotation in Sheather's sugar solution, measured, and photographed. Tissue samples from the intestine of a single positive bird were removed and placed in 10% neutral-buffered formalin for examination of coccidian endogenous stages.

RESULTS

A single Carolina wren (20%) was found to be passing a new species of Isospora. Oocysts of Isospora edwardwilsoni n. sp. were subspheroidal to ovoidal with a smooth bi-layered wall, measured (L × W) 23.8 × 20.3 µm, and had a length/width (L/W) ratio of 1.2; a micropyle and oocyst residuum was absent but typically one to up to four polar granule(s) was present. Sporocysts are ovoidal to ellipsoidal and measured 15.3 × 9.7 µm, L/W 1.6; a knob-like Stieda body was present as well as a distinct rounded sub-Stieda body. The sporocyst residuum was composed of various-sized granules in a compact irregular mass or dispersed between and across the sporozoite, or a combination of both within the same sporocyst. Information is also presented on the endogenous development of this coccidian.

CONCLUSION

This is the first coccidian reported from T. l. ludovicianus and, more importantly, the first known from the members of the family Troglodytidae in North America.

A new isosporoid coccidia (Apicomplexa: Eimeriidae)from the southern house wren Troglodytes musculus Naumann, 1823 (Passeriformes: Troglodytidae) from Brazil

A new isosporoid coccidian species (Protozoa: Apicomplexa: Eimeriidae) is reported from the southern house wren Troglodytes musculus, a very well distributed species in South and Central America. Isospora corruirae sp. nov. oocysts are subspherical to ovoidal, 24.1 × 21.4 μm, with smooth, bilayered wall. Micropyle and oocyst residuum are absent, but small spherules and splinter-like granules are frequently present. Sporocysts are ovoidal to piriform, 14.0 × 9.5 μm. Stieda body is prominent knob-like and substieda body is delicate. Sporocyst residuum is composed of scattered fragments of different sizes. Sporozoites are vermiform with posterior refractile bodies, anterior striations and a nucleus. This is the second description of an isosporoid coccidium infecting a New World wren.

Characterisation of Isospora lusitanensis n. sp. (Apicomplexa: Eimeriidae) from the Eurasian blackbird Turdus merula Linnaeus (Passeriformes: Turdidae) in mainland Portugal

A new coccidian species (Protozoa: Apicomplexa: Eimeriidae) is described from a specimen of the Eurasian blackbird Turdus merula Linnaeus held for rehabilitation and reintroduction into the wild in a centre for research and recovery of wild animals in Quinta de Marim, Olhão, Portugal. Isospora lusitanensis n. sp. has subspherical to ovoidal oöcysts, measuring on average 26.4 × 23.4 μm, with smooth, bi-layered wall c.1.1 μm thick. Micropyle and oöcyst residuum are absent, but a polar granule is present. Sporocysts are ellipsoidal, measuring on average 16.0 × 10.9 µm. Stieda body is knob-like and sub-Stieda body is prominent and rounded. Sporocyst residuum is composed of scattered spherules. Sporozoites are vermiform, with one refractile body and a nucleus. The morphological and morphometric data for the new species were compared with those for species parasitising birds of the Muscicapidae, Turdidae, Timaliidae, Troglodytidae and Cinclidae, which are considered phylogenetically close. The original histograms of Isospora turdi Schwalbach, 1959 were redrawn for comparison with I. lusitanensis n. sp. and a linear regression of width against length of the oöcysts is presented for characterisation. This is the first isosporoid coccidian described from T. merula in mainland Portugal.

A novel Isospora species (Apicomplexa: Eimeriidae) from warblers (Passeriformes: Parulidae) of Costa Rica

Five of 16 (31%) rufous-capped warblers (Basileuterus rufifrons) and 2 of 5 (40%) ovenbirds ( Seiurus aurocapilla ) sampled from Costa Rica were positive for a novel species of Isospora. Oocysts have a thin, smooth, double-layered, colorless wall and measure 22.3 μm ± 1.6 μm × 24.3 μm ± 1.5 μm (19-25 μm × 21-28 μm) with an average length-width (L/W) ratio of 1.0 (1-1.3). Oocyst residuum and micropyle are absent, but 0-4 spherical to cigar-shaped polar granules (1-2.5 μm) are present. Sporocysts are ovoid and measure 11.8 μm ± 0.9 μm × 16 μm ± 1.7 μm (10-14 μm × 12-19 μm) with an average L/W ratio of 1.6 (1.0-1.9). A knob-like Stieda body continuous with the sporocyst wall and a trapezoidal compartmentalized substieda body are present. Each sporocyst contained 4 sporozoites and a diffuse sporocyst residuum consisting of many variable-sized granules, some as large as 2 μm. This is the second description of an Isospora species in New World warblers (Passeriformes: Parulidae) and the first report of Isospora from both the rufous-capped warbler and ovenbird.