Aquatic Parasite Observatory

Auridistomum spp. (Stafford, 1905)

    • Species Name: Auridistomum spp. (Stafford, 1905)
    • Synonyms: Pterygotomaschalos (Stunkard, 1923); Tetrapapillatrema (Ralph, 1938)
    • Taxonomy: Animalia, Platyhelminthes, Trematoda, Plagiorchiida, Auridistomidae, Auridistomum spp.
    • Life Cycle: "Species of Auridistomum use snails as the first intermediate host (e.g., A. chelydrae uses Helisoma snails), the second intermediate host is amphibians (Frandsen and Madsen, 1979), and the definitive host of Auridistomum species is turtles" (Wharton, 1940).
    • Description:
      1. The ear-like, lateral projections of the mouth-sucker suggest Rhytidodes and Calycodes of Looss and Cotylotretus of Odhner, which the animal also resembles in its lengthened form, the testes being near the middle of the body, the long coeca, the uterus confined to a short region behind the sucker. Sections of the worm that was figured in my earlier paper show that the vitelline glands are not confined outside the coeca but continue from one side to the other, both above and below the coeca and excretory duct, and that they extend as far forward as to the posterior edge of the ventral sucker. The anterior follicles are not so numerous and are more difficult to distinguish from groups of sub-cuticular and gland cells. The position of the ovary, close behind and to the right from the ventral sucker, is an important distinction. Another is in the large median trunk of the excretory system, lying above the testes and dividing at the posterior boundary of the ovary, its lateral divisions rapidly narrowing. The Laurer's canal extends up in the crotch of the excretory duct and opens in the mid-dorsal line by a conspicuous thick-walled opening. There is a large penis-sac. The egg is elliptical and measures 0.031 x 0.017 mm. There is no apparent pre-pharynx or oesophagus. The oral and ventral suckers measure 0.307 x 0.276 and 0.230 x 0.199 in breadth and depth. The cuticle contains numerous fine scales. Each of the two ear-like projections of the wall of the mouth-sucker has a lateral pit above it.
    • Sources: Frabdsen, F. and Madsen, H. 1979. A review of Helisoma duryi in biological control. Acta Tropica, Vol. 36, p. 67-84.
    • Wharton, G.W. 1940. The Genera Telorchis, Protenes, and Auridistomum (Trematoda: Reniferidae). The Journal of Parasitology, Vol. 26, p. 497-518.
    • APO Parasite Records: (by Life Cycle)

Parasite Images:

  • University of Colorado Boulder