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Ultrastructural features of the tegumental surface of a new metacercaria, Nematostrigea sp. (Trematoda: Strigeidae), with a search for potential taxonomically informative characters

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The tegumental surface of a new strigeid metacercaria, Nematostrigea sp., which is a parasite of the freshwater fish Channa gachua (Hamilton) in central Vietnam, is described for the first time using scanning (SEM) and transmission (TEM) electron microscopy. In addition to the general tegumental surface in various parts of the body, details of the surface of the suckers, lappets and holdfast organ are presented, as are variations in the form and distribution of the body spines. As good taxonomic criteria are few in diplostomoid metacercariae at both specific and generic levels, a number of the ultrastructural features revealed may prove to represent taxonomically informative characters. These include the presence of: two rings of dome-shaped papillae localised at different levels on the rim of the oral sucker, a single ring of ciliated papillae on the inner margin of the ventral sucker and a band of dome-shaped papillae along the lateral margins of the broad body-fold in the ventral forebody; an unarmed oral sucker and anteroventral surface of the forebody, although the latter bears protuberant secretory pores; an armed ventral sucker covered by six-pointed spines, except on its rim; multi-pointed spines along the dorsal and ventral sides of the forebody, with the number of their teeth increasing posteriorly; multi-pointed spines on the forebody which gradually transform into single-pointed, more widely distributed spines on the hindbody, disappearing completely at posterior end of the body; the surface of the lappets with a particular distribution of pores leading to three types of secretory glands and three topographical modifications (areas where the surface is smooth, bears digitiform processes or bears recurved, dagger-shaped spines); and the surface of the holdfast organ which is covered with densely packed, straight or slightly curved, simple spines on its lateral surface but is smooth medially.

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  1. Abdel-Aal, A. A., Soliman, M. F. M., & Shalaby, I. M. (2004). Surface ultrastructure of Cardiocephalus longicollis (Digenea: Strigeidae) from herring gull, Larus argentatus, and its associated pathological lesions. Helminthologia, 41, 175–178.

  2. Abdul-Salam, J., & Sreelatha, B. N. S. (1993). Studies on cercariae from Kuwait Bay. II. Description and surface topography of Cercaria kuwaitae II sp.n. (Digenea, Cyathocotylidae). Acta Parasitologica, 38, 1–7.

  3. Arvy, I. (1954). Distomatose cêrébro-rachidienne due à Diplostomum phoxini (Faust), Hughes 1920, chez Phoxinus laevis Ag. Annales de Parasitologie Humaine et Comparée, 29, 510–520.

  4. Bell, A. S. (1995). Studies on the biosystematics and biology of strigeids (Digenea) parasitic in freshwater fish. PhD Thesis, Institute of Aquaculture, University of Stirling, 402 pp.

  5. Bell, A. S., Gibson, D. I., & Sommerville, C. (1997). Chaetotaxy and armature of Ichthyocotylurus erraticus (Rudolphi, 1809) and I. variegatus (Creplin, 1825) cercariae (Digenea, Strigeidae). Parasitology Research, 83, 70–76.

  6. Bennett, C. E. (1975). Scanning electron microscopy of Fasciola hepatica L. during growth and maturation in the mouse. Journal of Parasitology, 61, 892–898.

  7. Bhatti, I., & Johnson, A. D. (1972). Enzyme histochemistry of the holdfast and forebody gland cells of Alaria marcianae (La Rue, 1917) (Trematoda: Diplostomatidae). Proceedings of the Helminthological Society of Washington, 39, 78–87.

  8. Bibby, M. C., & Rees, G. (1971). The ultrastructure of the epidermis and associated structures in the metacercaria, cercaria and sporocyst of Diplostomum phoxini (Faust, 1918). Zeitschrift für Parasitenkunde, 37, 169–186.

  9. Combes, C. (1980). Atlas, mondial des cercairae. Mémoires du Muséum National d’Histoire Naturelle, Ser. A Zoologie, 115, 1–235.

  10. Conn, D. B., Goater, C. P., & Bray, D. (2008). Developmental and functional ultrastructure of Ornithodiplostomum ptychocheilus diplostomula (Trematoda: Strigeoidea) during invasion of the brain of the fish intermediate host, Pimephales promelas. Journal of Parasitology, 94, 635–642.

  11. 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, 703–714.

  12. Erasmus, D. A. (1969a). Studies on the host-parasite interface of strigeoid trematodes. VI. Ultrastructural observations on the lappets of Diplostomum phoxini Faust, 1918. Zeitschrift für Parasitenkunde, 32, 48–58.

  13. Erasmus, D. A. (1969b). Studies on the host-parasite interface of strigeoid trematodes. V. Regional differentiation of the adhesive organ of Apatemon gracilis minor Yamaguti, 1933. Parasitology, 59, 245–256.

  14. Erasmus, D. A. (1970a). The host-parasite interface of strigeoid trematodes. VII. Ultrastructural observation on the adhesive organ of Diplostomum phoxini Faust, 1918. Zeitschrift für Parasitenkunde, 33, 211–224.

  15. Erasmus, D. A. (1970b). The host-parasite interface of strigeoid trematodes. IX. A probe and transmission electron microscope study of the tegument of Diplostomum phoxini Faust, 1918. Parasitology, 61, 35–41.

  16. Erasmus, D. A., & Öhman, C. (1965). Electron microscope studies of the gland cells and host-parasite interface of the adhesive organ of Cyathocotyle bushiensis Khan, 1962. Journal of Parasitology, 51, 761–769.

  17. Fried, B., Irwin, S. W. B., & Lowry, S. F. (1990). Scanning electron microscopy of Echinostoma trivolvis and E. caproni (Trematoda) adults from experimental infections in the golden hamster. Journal of Natural History, 24, 433–440.

  18. Fujino, T., Ishii, Y., & Choi, D. W. (1979). Surface ultrastructure of the tegument of Clonorchis sinensis newly excysted juveniles and adult worms. Journal of Parasitology, 65, 579–590.

  19. Gibson, D. I. (1996). Trematoda. In: L. Margolis & Z. Kabata (Eds.), Guide to the parasites of fishes of Canada. Part IV. Canadian Special Publication of Fisheries and Aquatic Sciences No. 124. Ottawa: NRC Press, 373 pp.

  20. Gibson, D. I., & Bray, R. A. (1994). The evolutionary expansion and host-parasite relationships of the Digenea. International Journal for Parasitology, 24, 1213–1226.

  21. Higo, H., & Ishii, Y. (1984). Scanning electron microscopy of the newly excysted juveniles Paragonimus westermani (Kerbert, 1878) Braun, 1899 (parthenogenetic type) and P. miyazakii Kamo, Nishida, Hatsushika and Tominura, 1961. Japanese Journal of Parasitology, 33, 421–427.

  22. Higo, H., & Ishii, Y. (1987). Comparative studies on the surface ultrastructure of newly excysted metacercariae of Japanese lung flukes. Parasitology Research, 73, 541–549.

  23. Ibraheem, M. H. (2000). A light and electron microscope study on Diplostomum tregenna Nazmi Gohar, 1932 (Digenea: Diplostomatidae). Helminthologia, 37, 137–142.

  24. Jamjoom, M. B., & Shalaby, I. (2006). The contribution of electron microscopic studies to the taxonomy and biology of parasitic trematodes. World Journal of Zoology, 1, 64–81.

  25. Johnson, A. D., Bhatti, I., & Kanemoto, N. (1971). Structure and function of the holdfast organ and lappets of Alaria marcianae (La Rue, 1917) (Trematoda: Diplostomatidae). Journal of Parasitology, 57, 235–243.

  26. Jones, A., Bray, R. A., & Gibson, D. I. (Eds.). (2005). Keys to the Trematoda. Vol. 2. Wallingford: CAB International, 745 pp.

  27. Kobayashi, H. (1915). On the life-history and morphology of Clonorchi sinensis. Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten (und Hygiene), 75, 299–313.

  28. Køie, M. (1977). Stereoscan studies of cercariae, metacercariae, and adults of Cryptocotyle lingua (Creplin, 1925) Fischoeder, 1903 (Trematoda: Heterophyidae). Journal of Parasitology, 63, 835–839.

  29. Køie, M. (1985). On the morphology and life-history of Lepidapedon elongatum (Lebour, 1908) Nicoll, 1910 (Trematoda, Lepocreadiidae). Ophelia, 24, 135–153.

  30. Køie, M. (1992). Scanning electron microscopy of cercariae, metacercariae and adults of Pygidiopsis ardeae Køie, 1990 (Digenea, Heterophyidae). Parasitology Research, 78, 469–474.

  31. Komalamisra, C., Bunchuen, S., Waikagul, J., & Pongponratn, E. (2005). Chaetotaxy of newly excysted metacercariae among five species of Thai Paragonimus. Journal of Tropical Medical Parasitology, 28, 1–7.

  32. Lee, D. L. (1962). Studies on the function of the pseudosuckers and holdfast organ of Diplostomum phoxini Faust (Strigeida, Trematoda). Parasitology, 52, 103–112.

  33. Lim, D., Choi, K., Guk, S., Chai, J., Park, I., Park, Y., et al. (2008). Tegumental ultrastructure of adult Gynaecotyla squatarolae (Digenea: Microphallidae). Korean Journal of Parasitology, 46, 87–90.

  34. McKeown, C. A., & Irwin, S. W. B. (1995). The life cycle stages of three Diplostomum species maintained in the laboratory. International Journal for Parasitology, 25, 897–906.

  35. Mouahid, A. (1989). Szidatia joyeuxi (Trematoda, Cyathocotylidae): morphological and tegumental changes during growth in the definitive host. Systematic Parasitology, 13, 125–134.

  36. Niewiadomska, K. (2002). Superfamily Diplostomoidea Poirier, 1886. In: D. I. Gibson, A. Jones, & R. A. Bray (Eds.), Keys to the Trematoda. Vol. 1. Wallingford: CAB International, pp. 159–166.

  37. Öhman, C. (1965). The structure and function of the adhesive organ in strigeid trematodes. Part II. Diplostomum spathaceum Braun, 1893. Parasitology, 55, 481–502.

  38. Öhman, C. (1966a). The structure and function of the adhesive organ in strigeid trematodes. Part III. Apatemon gracilis minor Yamaguti, 1933. Parasitology, 56, 209–226.

  39. Öhman, C. (1966b). The structure and function of the adhesive organ in strigeid trematodes. IV. Holostephanus lühei Szidat, 1936. Parasitology, 56, 633–637.

  40. Pekkarinen, M. (1986). Development of the cercaria of Lacunovermis macomae (Trematoda: Gymnophallidae) to the metacercaria in brackish-water Macoma balthica. Annales Zoologici Fennici, 23, 237–250.

  41. Podvyaznaya, I. M. (1999). The fine structure of the tegument of cercariae and developing metacercariae of Diplostomum chromatophoprum (Trematoda: Diplostomidae). Parazitologiya, 33, 507–519. (In Russian).

  42. Ramadan, M. A., & Ibraheem, M. H. (2000). A contribution to the surface ultrastructure of adult Cynodiplostomum azimi (Gohar, 1933) Dubois, 1936 (Digenea: Cynodiplostomatidae): with special reference to its internal anatomy. Journal of the Union Arab Biologists, Cairo, Zoology, 13A, 531–544.

  43. Rushton, W. (1937). Blindness in freshwater fish. Nature, 140, 1014.

  44. Scholz, T., Ditrich, O., Tuma, M., & Giboda, M. (1991). Study of the body surface of Haplorchis yokogawai (Katsuta, 1932) and H. taichui (Nishigori, 1924) (Trematoda: Heterophyidae). Southeast Asian Journal of Medicine and Public Health, 22, 443–448.

  45. Shigin, A. A. (1986). Trematodes of the fauna of the USSR. Genus Diplostomum metacercariae. Moscow: Academii Nauk SSSR, 253 pp. (In Russian).

  46. Shoop, W., & Corkum, K. C. (1984). Tegumental changes of Alaria marcianae (Trematoda) during migration in the domestic cat. Journal of Parasitology, 70, 244–252.

  47. Whittington, I. D., & Cribb, B. W. (2001). Adhesive secretions in the Platyhelminthes. Advances in Parasitology, 48, 101–223.

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The authors would like to thank the workers of the Coastal Department of the Russian-Vietnamese Tropical Centre in Vietnam for their continuous support and the staff of the Centre of Electron Microscopy, Institute of Biology of Inland Waters, Russia. The present study was supported by the Russian Foundation for Fundamental Research (project no. 09-04-00342a).

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Correspondence to Larisa G. Poddubnaya.

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Poddubnaya, L.G., Mishina, E., Zhokhov, A.E. et al. Ultrastructural features of the tegumental surface of a new metacercaria, Nematostrigea sp. (Trematoda: Strigeidae), with a search for potential taxonomically informative characters. Syst Parasitol 75, 59 (2010). https://doi.org/10.1007/s11230-009-9207-5

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  • Ventral Sucker
  • Oral Sucker
  • Scanning Electron Microscopical Measurement
  • Simple Spine
  • Sensory Papilla