Two New Menosporine Gregarines, Hoplorhynchus acanthatholius N. Sp. and Steganorhynchus dunwoodyi N. G., N. Sp. (Apicomplexa: Eugregarinorida: Actinocephalidae) from Coenagrionid Damselflies (Odonata: Zygoptera)

ABSTRACT. Hoplorhynchus acanthatholius , n. sp. is described from Enallagma civile , the Civil Bluet damselfly. Trophozoites are solitary, lie in the mesenteron between the peritrophic membrane and the epithelium, and attain a maximum length of 850 μm. Epimerite ovoid to broadly ovoid; anterior margin bearing eight equidistant retroarcuate hooks; attached to protomerite by means of a vermicular stalk. Protomerite ovoid; deutomerite narrowly obvoid. Gametocysts spherical; diam 300 μm, sporulating by simple dehiscence in 48–72 h. Oocysts are characteristic of Menosporinae: smooth, biconical, crcscentic, uniform in size and shape. Steganorhynchus dunwoodyi , n. g., n. sp. is described from the damselfly Ischnura verticalis. The genus is characterized by an epimerite comprising an ovoid papilla enclosed in a retractable, globular sheath, borne on a long vermicular stalk. Trophozoites are solitary, lie in the mesenteron between the peritrophic membrane and epithelium, and attain a maximum length of 605 μm. Protomerite very broadly ovoid; deutomerite obvoid. Gametocysts spherical; diam 258 μm, sporulating by simple dehiscence in 48–72 h. Oocysts are characteristic of Menosporinae: smooth, biconical, crescentic, uniform in size and shape. The population dynamics of H. acanthatholius and S. dunwoodyi among damselfly populations in five Nebraska localities are presented.