ISOSPORA-SAGITTULAE, A NEW COCCIDIAN PARASITE (APICOMPLEXA, EIMERIIDAE) FROM THE SPOTTED ANTBIRD (HYLOPHYLAX-NAEVIOIDES)

Isospora sagittulae n. sp. is a coccidian parasite here described from the fecal contents of three of three (100%) spotted antbirds (Hylophylax naevioides) collected in rain forests of northwestern Ecuador. Oocysts of I. sagittulae are ovoid to ellipsoid, 27.5 x 21.8 (25-30 x 21-24) mum, colorless, with a smooth, double-layered wall; shape index (length/width) is 1.27 (1.2-1.4). A micropyle and oocyst residuum are absent, but the oocyst contains 1-3 (usually 2-3) polar bodies. Sporocysts are subspherical to ovoid, 14.8 x 12.4 (13-16 x 12-13) mum, with a smooth, single-layered wall, a thin, dense Stieda body, and an arrow-head or triangular-shaped substieda body that protrudes into the Stieda body; shape index is 1.19 (1.1-1.3). Sporozoites have one prominent ovoid, posterior refractile body and a small, ovoid centrally located nucleus; they appear to be stuffed randomly among scattered residuum in the sporocyst. Several unidentified tapeworm onchospheres also were found in one of the fecal samples.