The fine structure and function of the adult epidermis of two skin parasitic monogeneans, Entobdella soleae and Acanthocotyle elegans

Abstract

Electron-microscope investigations on the outer layers of parasitic platyhel-minths have so far neglected the monogeneans and have been confined to the endoparasitic digeneans and cestodes (Braten, 1968; Burton, 1966; Charles & Orr, 1968; Erasmus, 1967; Lumsden, 1966; Morris & Threadgold, 1967; Race, Larsh, Esch & Martin, 1965; Rothman, 1968; Threadgold, 1965). For this reason the covering layer of monogeneans is still referred to as a ‘cuticle’ even though it is unlikely to be so since the surface of the endoparasitic platyhelminths has been shown to be a living cytoplasmic ‘epidermis’ (see Lee, 1966) which, as pointed out by Erasmus (1967) and Lumsden (1966), constitutes a metabolically active inter-face with host tissues and fluids. Two main considerations prompted the present investigations of the covering layer of monogeneans. First, it was hoped that a comparison of the covering layer of these ectoparasites with that of the digeneans and cestodes might help to define particular specializations of this layer associated specifically with the ectoparasitic or endoparasitic habit; secondly, because ectoparasitism can, in an evolutionary sense, be considered as a transitional state between a free-living and an endoparasitic existence (see Llewellyn, 1965), it was felt that this work on monogeneans could assist an understanding of the evolution of the platyhelminth outer layer.

Surface Topography of the Anterior Adhesive Apparatus of the Gill Monogenean Parasite Diplectanum sp. diesing, 1858, with some Surface Criteria

“…Moreover, the thin thickness of the head lobes tegument compared to that of the other body tegument is thought to. The present study supports [28] hypothesis, in that the stubby microvilli of the adhesive apparatus helping Diplectanum sp. to mix and spread sticky different secretions of gland cells as a tacky film over the host during locomotion.…”

“…is not known. However, it was suggested by [28,8] these microvilli may assist in spreading and mix the secretory materials of different gland cells and increase the surface area available for binding the adhesive secretion of the head region during locomotion. In this respect, absence of microvilli from the rest of the head region may complete the action of the presence of microvilli of the adhesive sacs.…”

Cholinergic and aminergic elements in the nervous system of Pseudodactylogyrus bini (Monogenea)

“…Cholinergic elements (AThChE, AchE, ChE) have been detected in the nervous system of monogeneans in several studies (Halton & Jennings 1964, Halton & Morris 1969, Lyons 1969, 1970, Tinsley & Wynne Owen 1975, Venkatanarsaiah 1981, Shaw 1982, Buchmann & Mellergaard 1988. A number of aminergic and peptidergic elements have been found in the nervous system of invertebrates (Van Noorden 1984, Falkmer et al 1985, O'Shea & Schaffer 1985, Gustafsson et al 1986) including some monogeneans (Reuter 1987, Maule et al 1988.…”

Revue bibliographique. Ultrastructure des Monogènes : liste des espèces et des organes étudiés

“…External morphology, SEM LYONS, 1970aLYONS, 1973aLYONS, 1969aLYONS, 1973bLYONS, 1969aLYONS, 1969b 19781980a1980a1980a1980aCOMBES &VAGO, 1975VAGO& COMBES, 19761980a1980b1980a1980a1980a1980a1980a1980a Chimaericola leptogaster Eggs, SEM External morphology, SEM…”

“…Pêche Piscic. (1993 , 1986, OLIVER, 1976aOLIVIER, 1976bCONE, GRATZEK & HOFFMAN, 1987LYONS, 1970aLYONS, 1973bEL-NAGGAR & KEARN, 1983FOURNIER, 1980aCONE & ODENSE, 1988HARRIS & TINSLEY 1987MEHLHORN et al, 1988SCHMAHL, MEHLHORN & HABERKORN, 1988CONE & CUSACK, 1988KRITSKY & KRUIDENIER, 1976MALMBERG & MALMBERG, 1986MALMBERG, 1987MALMBERG, 1988CONE & CUSACK, 1988LYONS, 1970aKRITSKY, 1978CONE & ODENSE, 1984THULIN, HÔGLUND & LINDESJÔÔ, 1989HALTON in FRIED & HASEEB, 1991MALMBERG & FERNHOLM, 1989MALMBERG & FERNHOLM, 1989MALMBERG & FERNHOLM, 1991DUOBINIS-GRAY TOOLE & CORKUM, 1985HARRIS, 1983BUCHMANN, K0IE & PRENT0, 1987 BUCHMANN, 1988a;BUCHMANN, 1988bKEARN & GOWING, 1989KEARN in FRIED & HASEEB, 1991CONE, 1979CONE & BURT, 1981RAMASAMY & HANNA, 1986aAGRAWAL & SHARMA, 1990PASCOE, 1987PICHELIN, WHITTINGTON & PEARSON, 1991PASCOE, 1987MORRIS, 1973HALTON, 1979 IRWIN ;n FRIED & HASEEB, 1991WRIGHT & DECHTIAR, 1974…”