Abstract
The ultrastructure of the tegument of the sporocyst and contained cercariae of Meiogymnophallus minutus found in Scrobicularia plana collected in Ria de Aveiro estuary (Portugal) were studied by scanning (SEM) and transmission electron microscopy (TEM). TEM revealed microvilli extending from the surface of the sporocyst tegument that contributed to the lacetrimmed surface morphology observed by SEM. The cercarial surface was papilliform and covered densely with single-pointed tegumental spines. On TEM, besides the spines and several mitochondria, translucid and electron-dense spherical secretory vesicles were evident in the matrix of the tegument but were not seen on the sporocyst tegument. Uniciliate sensory receptors found in the cercaria of M. minutus were examined under SEM and TEM. Structural differences between the oral and the ventral sucker were observed. On the lip of the ventral sucker, large and strong spines were arranged in concentric rows, and two groups of six sensory papillae were placed concentrically and equidistantly. The oral sucker, surrounded by a crown of dense and long microvilli, exhibited a ring of uniciliate sensory papillae and some tegumental spines along the lip. The surface morphology of the M. minutus cercaria is compared with that of other Gymnophallidae cercariae.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Abdul-Salam J, Sreelatha BNS (1993) Studies on cercariae from Kuwait Bay. II Description and surface topography of cercaria kuwaitae II sp. n. (Digenea, Cyathocotylidae). Acta Parasitol 38: 1–7
Al-Salman HAM (1984) Studies on the biology of marine Digenea: Meiogymnophallus minutas (Cobbold, 1859) Bowers and James, 1967. Ph. D. Thesis, University College, Swansea
Al-Salman HA, James BL (1988) Ultrastructure of the tegument in daughter sporocyst and cercarial embryos of Meiogymnophallus minutas (Digenea: Gymnophallidae). Int J Parasitol 18: 231–242
Benjamin R, James BL (1987) The development of metacercaria of Maritema linguilla Jäg, 1908 (Digenea: Microphallidae) in the intermediate host, Ligia oceanica. Parasitology 94: 221–231
Bogitsh BJ (1986) An overview of surface specializations in the digenetic trematodes. Hydrobiologia 132: 305–310
Bowers EA, James BL (1967) Studies on the morphology, ecology and life-cycle of Meiogymnophallus minutus (Cobbold, 1859) comb. nov. (Trematoda: Gymnophallidae). Parasitology 57: 281–300
Bowers EA, Bartoli P, James BL (1990) A demonstration of allopatric sibling species within the Gymnophallidae (Digenea). Syst Parasitol 17: 143–152
Dunn TS, Hanna REB, Nizami WA (1987a) Ultrastructural and cytochemical observation on the tegument of three species of paramphistomes (Platyhelminthes: Digenea) from the Indian water buffalo, Bubalus bubalis. Int J Parasitol 17: 1153–1161
Dunn TS, Hanna REB, Nizami WA (1987b) Sensory receptors of the miracidium of Gigantocotyle explanatum (Trematoda: Paramphistomidae). Int J Parasitol 17: 1131–1140
Fried B, Awatramani R (1992) Light and scanning electron microscopical observations of the daughter rediae of Echinostoma trivolvis (Trematoda). Parasitol Res 78: 257–259
Halton DW, McCrae JM (1985) Development of the tegument and alimentary tract in a digenetic trematode, Fellodistomum fellis. Parasitology 90: 193–204
Hong SJ, Chai JY, Lee SH (1991) Surface ultrastructure of the developmental stages of Heterophyopsis continua (Trematoda: Heterophyidae). J Parasitol 77: 613–620
James BL (1969) The Digenea of the intertidal prosobranch, Littorina saxatilis (Olivi). Z Zool Syst Evolutionsforsch 7: 273–316
Koie M (1985)The surface topography and life-cycles of digenetic trematodes in Limanda limanda (L.) and Gadus morhua (L.). D. Sc. Thesis, University of Copenhagen
Koie M (1992) Scanning electron microscopy of cercaria, metacercariae and adults of Pygidiosis ardeae Koie, 1990 (Digenea, Heterophyidae). Parasitol Res 78: 469–474
Kruse DM, Hosier DW, Fried B (1992) The expulsion of Echinostoma trivolvis (Trematoda) from ICR mice: scanning electron microscopy of the worms. Parasitol Res 78: 74–77
Loos-Frank B (1971) Zur Kenntnis der gymnophalliden Trematoden des Nordseeraumes. Z Parasitenkd 36: 206–232
Matthews BF, Matthews RA (1988) The tegument in hemiuridae (Digenea: Hemiuroidea): structure and function in the adult. J Helminthol 62: 305–316
Mouahid A (1989) Szidatia joyeuxi (Trematoda: Cyathocotylidae): morphological and tegumental changes during growth in the definitive host. Syst Parasitol 13: 125–134
Pariselle A, Matricon-Gondran M (1985) A new type of ciliated sensory receptor in the cercariae of Nicolla gallica (Trematoda). Z Parasitenkd 71: 353–364
Pekkarinen M (1986) Development of the cercaria of Lacunovermis macomae (Trematoda: Gymnophallidae) to the metacercaria in brackish-water Macoma balthica (Bivalvia). Ann Zool Fenn 23: 237–250
Pekkarinen M (1987a) The cercaria of Lacunovermis macomae (Lebour, 1908) (Trematoda: Gymnophallidae), and its penetration into the bivalve Macoma balthica (L.) in experimental conditions. Ann Zool Fenn 24: 101–121
Pekkarinen M (1987b) The cercaria and metacercaria of Gymnophallus gibberosus Loos-Frank, 1971 (Trematoda: Gymnophallidae) in Macoma balthica (L.) (Bivalvia) in the Baltic brackish water (southwestern Finland). Ann Zool Fenn 24: 123–136
Pekkarinen M, Ching HL (1994) Comparisons of gymnophallid digeneans from North Pacific and Baltic clams, Macoma balthica (Bivalvia). J Parasitol 80: 630–636
Rohde K, Watson NA (1992) Ultrastructure of the developing protonephridal system of the cercaria of Philophathalmus sp. (Trematoda, Digenea). Parasitol Res 78: 368–375
Russell-Pinto F (1990) Differences in infestation intensity and incidence of hinge and mantle margin Meiogymnophallus minutus metacercariae (Gymnophallidae) in Cerastoderma edule (Bivalvia): possible species coexistence in Ria de Aveiro. J Parasitol 76: 653–659
Russell-Pinto F, Bartoli P (1992) Sympatric distribution of Meiogymnophallus minutus and M. fossarum (Digenea: Gymnophallidae) in Cerastoderma edule in the Ria de Aveiro estuary in Portugal. Parasitol Res 78: 617–618
Scholz T, Ditrich O, Giboda M (1992) Study on the surface morphology of the developmental stages of the liver fluke, Opisthorchis viverrini (Trematoda: Opisthorchiidae). Ann Parasitol Hum Comp 67: 82–90
Zdárská Z (1992) Transmission electron microscopy of sensory receptors of Echinostoma revolutum (Froelich 1802) cercaria (Digenea: Echinostomatidae). Parasitol Res 78: 598–606
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Russell-Pinto, F., Bowers, E. & James, B. Ultrastructure study of the intramolluscan stages of Meiogymnophallus minutus (Digenea: Gymnophallidae) in Scrobicularia plana (Bivalvia) from Portugal. Parasitol Res 82, 428–434 (1996). https://doi.org/10.1007/s004360050140
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s004360050140