title: Bacillidium cyclopis Vávra, 1962 - Description of the ultrastructural cytology and transfer to the genus Mrazekia Léger and Hesse, 1916 (Microspora, Mrazekiidae).
abstract: The ultrastructural cytology of the microsporidium Bacillidium cyclopisVávra, 1962, a parasite of the copepod Acantho cyclop s americanus in Czechoslovakia, is described, with emphasis on the mature spore. All life cycle stages are diplokaryotic. The three-layered spore wall has a stratified exospore. The polaroplast has two distinctly separated lamellar parts where the lamellae are folded concentrically around the anterior part of the polar filament. Anterior lamellae are narrow and closely packed; posterior lamellae are wider and more loosely arranged. The polar filament has an anterior straight and wide section, the "manubrium", where the posterior third is widened in a characteristic manner, and a final section, arranged in 2-3 narrow, isofilar coils. The attachment of the polar filament is more or less oblique in relation to the long axis of the spore. The ejected filament leaves the spore in a distinct angle, and the narrow part is characteristically and regularly coiled. Glycoconjugates are present in the layers of the anchoring disc, in one of the external layers of the manubroid part of the polar filament, and in two distinct layers of the coils. The diplokaryon partially encloses the manubrium in a mantle-like fashion. B. cyclopis is compared to re-examined preparations of Mrazekia argoisiiLéger and Hesse, 1916. These two species are the only Bacillidium-like microsporidia of Crustacea, and they are distinguished from all the other Bacillidium-like microsporidia by their swollen posterior end of the manubrium. This character, which is easily seen also using light microscopy, is considered diagnostic for the genus Mrazekia, and B. cyclopis is transferred to this genus. Mrazekiidae Léger and Hesse, 1922 is the valid family name, with Bacillidiidae Larsson, 1986 as a junior synonym.
authors.affiliation: Department of Zoology, University of Lund, Sweden.
authors.forename: J I
authors.initials: JI
authors.lastname: Larsson
authors.forename: J
authors.initials: J
authors.lastname: Vávra
authors.forename: J
authors.initials: J
authors.lastname: Schrével