Ultrastructure of musculature of the marginal hooklets of Macrogyrodactylus congolensis, a monogenean skin parasite from the catfish Clarias gariepinus

Abstract

The musculature of the marginal hooklets of adult Macrogyrodactylus congolensis (Prudhoe, 1957) Yamaguti, 1963 has been studied. Each marginal hooklet of M. congolensis is associated with three pairs of muscles. The possible role of these muscles in the operation of the marginal hooklet is discussed. Transmission electron microscopy has been used for the first time to study the marginal hooklets of M. congolensis. The handle articulates with the blade in the region of the guard. Internally, the handle, the proximal region of the blade in the articulation region and the distal pointed region of the blade consist of three layers. Distal to the articulation region, the blade consists of four layers with differing electron densities. A cavity is associated with the distal region of the blade and the handle. A cyton containing secretory bodies of different sizes and shapes was found in association with each marginal hooklet. The possible function of these secretions is discussed. © 2011 Versita Warsaw and Springer-Verlag Wien.