On the cytology and life cycle of Cougourdella polycentropi weiser, 1965, with comments on the taxonomy of the genus Cougourdella hesse, 1935 (microspora, cougourdellidae)

Abstract

The cytology and life cycle of a microsporidium identified as Cougourdella polycentropi, with provenance from southern Sweden, is described using light and electron microscopy methods. The life cycle is comprised of two merogonial cycles followed by tetrasporoblastic sporogony in sporophorous vesicles. The lageniform, 7.0-7.7 μm long spores have an anisofilar polar filament arranged in 6-7 coils, a layered exospore and chambered/lamellar polaroplast of unusual construction. The sporophorous vesicles have fibrillar, and temporarily, tubular inclusions. The vesicles were fragile and the tetrasporoblastic condition was not prominent in squash preparations. The microsporidium is compared to microsporidia with lageniform spores from caddis fly hosts, and the identification is discussed. The taxonomic problems with the genera Pyrotheca and Cougourdella are discussed.