A Dermocystidium infection in Trichomycterus sp. (Osteichthyes, Trichomycteridae)

Abstract

Two whitish elongate cysts in the left pectoral fin of Trichomycterus sp. (Osteichthyes, Trichomycteridae) were packed with Dermocystidium sp. spores. The spores were spherical and had a large PAS positive central refractile body, the cytoplasm being restricted to a narrow peripheral layer containing the nucleus. The cysts were surrounded by a thin homogeneous wall of parasite origin, and there was no encapsulation of the cysts by host tissue.