Aquatic Parasite Observatory

Nyctotherus spp. (Leidy, 1849)

    • Species Name: Nyctotherus spp. (Leidy, 1849)
    • Synonyms: None
    • Taxonomy: (Leidy, 1849) Protista, Ciliophora, Spirotrichea, Clevelandellida, Nyctotheridae, Nyctotherus spp.
    • Life Cycle: The lifecycle of Nyctotherus is coordinated with the breeding cycle of the host. During the non-breeding season, the parasite is in the trophozoite form and only reproduces by binary fission occasionally. As the breeding season approaches, the reproduction methods change from asexual to sexual and the trophozoites division rate increases. Eventually, mononuclear cycst are formed and passed into the water with feces. The new host is reinfected when the cyst is eaten (Smyth and Wakelin, 1994).
    • Description:
      1. Oval, compressed; peristome beginning at anterior end, turning to right, and ending in cytosome mudway; cytopharynx running dorsally and posteriorly, forming a long tube with undulating membrane. Massive macronucleus present anteriorly; micronucleus present anteriorly; cytopyge and contractile vacuole terminal; in colon of invertebrates, amphibia, and fishes.
    • Sources: Hoffman, G.L. 1999. Parasites of North American Freshwater Fishes. Second Edition, p. 40.
      Smyth, J.D. and Wakelin, D. 1994. Introduction to Animal Parasitology. Third edition, p. 152. Cambridge University Press; Cambridge, New York & Melbourne.
    • APO Parasite Records: (by Life Cycle)

Parasite Images:

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