Scanning electron microscopy on Gotocotyla acanthura (Monogenea, Gotocotylidae) from Pomatomus saltatrix (Ostheichthyes, Pomatomidae) in Brazil / Microscopia eletrônica de varredura de Gotocotyla acanthura (Monogenea, Gotocotylidae) parasita de Pomatomus saltatrix (Ostheichthyes, Pomatomidae) no Brasil

Gotocotyla acanthura (Parona & Perugia, 1896) Meserve, 1938 collected from the gills of Pomatomus saltatrix from the coast of the state of Rio de Janeiro state was analyzed using scanning electron microscopy (SEM). The study demonstrated the presence of a buccal cavity, a genital atrium on the ventral surface and a muscular structure on the dorsal surface at the level of the body constriction. An elongated haptor with 80 to 120 pedunculated clamps symmetrically distributed in two rows, with rib-like thickenings and a curved lappet bearing a pair of hooks at the posterior extremity of the body were also observed. The cirrus could be seen protruding from the genital atrium, armed with pectinate spines along its length and presenting up to eight pointed spines around the genital atrium.

Gotocotyla acanthura (Parona & Perugia, 1896) Meserve, 1938, coletado das brânquias de Pomatomus saltatrix do litoral do Estado do Rio de Janeiro, foi estudado por microscopia eletrônica de varredura (MEV). O estudo demonstrou a presença de uma cavidade bucal, átrio genital na superfície ventral e uma estrutura muscular na superficie dorsal ao nível da constricção do corpo. Na extremidade posterior do corpo, foi observado o haptor alongado, apresentando 80 a 120 pinças pedunculadas, distribuídas em duas fileiras simétricas e uma porção terminal curvada provida de um par de ganchos. O cirro foi visualizado projetando-se do átrio genital, armado com espinhos pectinados ao longo do seu comprimento, apresentando até 8 espinhos pontiagudos ao redor do átrio.

Ultrastructure and cytochemistry of the tegument of Atriaster heterodus (Platyhelminthes: Monogenea)

The tegument of the polyopisthocotylean monogenean Atriaster heterodus Lebedev & Parukhin, 1969 was studied using transmission electron microscopy. The outer syncytial layer of the tegument is connected to the internal cell bodies by cytoplasmic extensions which interweave between the muscular fibres. The free surface of the syncytium has projections of the external membrane which are similar to microvilli. The undulating basal membrane, with numerous narrow elongate projections, is associated with the basal lamina situated between the syncytial and muscular layers. The cell bodies and syncytial layer of the tegument exhibit two types of vesicles, one with fibrous contents and one with electron-dense contents; these were analysed using two cytochemical tests, the E-PTA and alcian blue methods, used for the first time on monogeneans

The ultrastructure of the gastrodermis and the nutrition of the gill parasitic Atriaster heterodus Lebedev and Paruchin, 1969 (Platyhelminthes: Monogenea)

The gastrodermis of Atriaster heterodus Lebedev & Paruchin, 1969 (Polyopisthocotylea), a gill parasite from Diplodus argenteus (Valenciennes, 1830), is composed of "U"-shape hematin cells and a connecting syncytium, both having cytoplasmic lamellae. These cells show outgrowths and bent folds which were seen to enclose lumen material. The trapped material was then subjected to endocytosis. The nature of ingested food material was comparatively analysed by cytochemical and histochemical tests. Blood residues were detected in the gut but tests for mucins were negative. No intact erythrocytes were observed in the gut lumen.