Aquatic Parasite Observatory

Clinostomum spp. (Leidy, 1856)

    • Species Name: Clinostomum spp. (Leidy, 1856)
    • Synonyms: None
    • Taxonomy: (Leidy, 1856) Animalia, Platyhelminthes, Trematoda, Plagiorchiida, Clinostomidae, Clinostomum spp.
    • Life Cycle: Clinostomatids are typically found as adults in the mouth or esophagus of aquatic reptiles and birds. Miracidia develop in eggs that leave the bird and in the water the miracidia hatch and penetrate a snail host. After sporocyst and redial generations, brevifurcate, pharyngeate cercariae with pigmented eye spots are produced. These cercariae seek out fresh-water fish which they penetrate and then encyst as metacercariae in muscle and connective tissues. The metacercaria contains some reproductive structures and takes only a few days to develop to the adult stage after a fish is eaten by a final host (Ortlepp, 1963).
    • Description:
      1. Body medium to large, linguiform, stout, convex dorsally and concave ventrally. Oral sucker surrounded by collar-like fold when retracted. Ventral sucker muscular, well developed. Caeca long, simple, with more or less sinuous wall, especially in anterior half body, but without long lateral branches or diverticula. Testes smooth or irregular in shape, in posterior half of body. Cirrus-sac and genital pore pretesticular or lateral to anterior testis. Ovary intertesticular, submedian. Vitelline follicles in lateral fields between posterior extremity and level of ventral sucker. Uterus intercaecal, between Mehlis' gland and ventral sucker. Cosmopolitan.
    • Sources: Bray, R.A., Gibson D.I., and Jones, A. 2002. Keys to the Trematoda, Volume 1 p. 117.
      Ortlepp, R.J. 1963. Clinostomid trematodes as aberrant parasites in the mouth of the domestic cat (Felis catus domesticus). Onderstepoort J Vet Res., Vol. 30, p. 137-144. Posted by American Association of Veterinary Parasitology at
    • APO Parasite Records: (by Life Cycle)

Parasite Images:

Distribution Map:

  • University of Colorado Boulder