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Ultrastructure of the tegument of the metacercaria of Timoniella imbutiforme

  • H.E.M. El-Darsh (a1) and P.J. Whitfield (a1)


The spinous body tegument of the metacercaria of Timoniella imbutiforme (Molin, 1859) is described in detail and found to comprise an outer tegumental syncytium connected to subjacently situated subtegumentary ‘cells’. There are four types of secretory bodies in the outer syncytial layer as well as serrated overlapping spines and mitochondria. The subtegumentary ‘cells’ are characterized by the presence of four secretory body types as well as giant bodies which may be involved in the elaboration of the secretory bodies or spine material. The normal configuration of the somatic muscles of T. imbutiforme show that the muscular machinery necessary for activity once the larval stage becomes excysted is already in place. The sensory endings are found to be of the uniciliate type occurring in groups of up to eight in raised domes distributed over the body. Secretory gland cells are numerous and possess long ducts connected to the basal lamina of the outer syncytial layer via septate desmosomes.


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Aikawa, M. & Atkinson, C.T. (1990) Immunoelectron microscopy of parasites. Advances in Parasitology 29, 151214.
Apinhasmit, W., Sobhon, P., Saitongdee, P., Menayotin, S. & Upatham, E.S. (1994) Opisthorchis viverrini: Ultrastructure of the tegument of the first-week juveniles and adult flukes. International Journal for Parasitology 24, 613621.
Bennett, C.E. & Threadgold, L.T. (1973) Electron microscope studies of Fasciola hepatica. XIII. Fine structure of newly excysted juvenile. Experimental Parasitology 34, 8599.
Brooks, D.R. (1980) Revision of the Acanthostominae Poche, 1926 (Digenea: Cryptogonimidae). Zoological Journal of the Linnean Society 70, 313382.
Burton, P.R. (1966) The ultrastructure of the integument of the frog bladder fluke Gorgoderina sp. Journal of Parasitology 52, 926934.
Dunn, T.S., Dang, P.H., Mattison, G., Hanna, R.E.B. & Nizami, W.A. (1992) Ultrastructural observations on the redial tegument of Paramphistomum epiclitum from the planorbid snail, Indoplanorbis exustus. Journal of Helminthology 66, 167176.
El-Darsh, H. & Whitfield, P.J. (1999) Digenean metacercariae (Timoniella spp., Labratrema minimus and Cryptocotyle concava ) from the flounder, Platichthys flesus L., in the tidal Thames. Journal of Helminthology 73, 103113.
Erasmus, D.A. (1967) The host-parasite interface of Cyathocotyle bushiensis Khan, 1962 (Trematoda: Strigeoidea) II. Electron microscope studies of the tegument. Journal of Parasitology 53, 703714.
Fujino, T., Ishii, Y. & Choi, D.W. (1979) Surface ultrastructure of the tegument of Clonorchis sinensis newly excysted juveniles and adults. Journal of Parasitology 65, 579590.
Hockley, D.J. (1973) Ultrastructure of the tegument of Schistosoma. Advances in Parasitology 11, 233297.
Køie, M. (1971) On the histochemistry and ultrastructure of the tegument and associated structures of the cercariae of Zoogonoides viviparus in the intermediate host. Ophelia 9, 165206.
Køie, M. (1973) The host-parasite interface and associated structures of the cercariae and adult Neophasis lageniformis (Lebour, 1910). Ophelia 12, 205219.
Kuntz, S.M., Font, W. & Wittrock, D.D. (1982) Ultrastructure of the tegument of Amblosoma suwaense metacercariae. Proceedings of the Helminthological Society of Washington 49, 148151.
LeFlore, W.B. & Bass, H.S. (1983) Observations on the morphology and hydrolytic enzyme histochemistry of excysted metacercariae of Himasthla rhigedana (Trematoda: Echinostomatidae). International Journal for Parasitology 13, 179183.
Mattison, R.G., Hanna, R.E.B. & Nizami, W.A. (1994) Ultrastructure and histochemistry of the tegument of juvenile paramphistomes during migration in Indian ruminants. Journal of Helminthology 68, 211221.
McDowall, A.A. & James, B.L. (1988) The functional morphology of the circumoral spines of Timoniella imbutiforme (Molin, 1859) Brooks, 1980 (Digenea: Acanthostomidae). International Journal for Parasitology 18, 523530.
Rees, G. (1974) The ultrastructure of the body wall and associated structures of the cercariae of Cryptocotyle lingua (Creplin) (Digenea: Heterophyidae) from Littorina littorea (L.). Zeitschrift für Parasitenkunde 44, 239265.
Robinson, R.D. & Halton, D.W. (1983) Functional morphology of the tegument of Corrigia vitta (Trematoda: Dicrocoeliidae). Zeitschrift für Parasitenkunde 69, 319333.
Smyth, J.D. & Halton, D.W. (1983) The physiology of trematodes. Cambridge, Cambridge University Press.
Threadgold, L.T. (1963a) The tegument and associated structures of Fasciola hepatica. Quarterly Journal of Microscopical Science 104, 505512.
Threadgold, L.T. (1963b) The ultrastructure of the ‘cuticle’ of Fasciola hepatica. Experimental Cell Research 30, 238242.
Threadgold, L.T. (1968) The tegument and associated structures of Haplometra cylindracea. Parasitology 58, 17.
Wilson, R.A. & Barnes, P.E. (1974) The tegument of Schistosoma mansoni: observations on the formation, structure and composition of cytoplasmic inclusions in relation to tegument function. Parasitology 68, 239258.

Ultrastructure of the tegument of the metacercaria of Timoniella imbutiforme

  • H.E.M. El-Darsh (a1) and P.J. Whitfield (a1)


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