• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.217-226
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• 1991

Three morphological types of the genus Metagonimus were found encysted in the dace, Tribolodon tacganowskii, caught from the Sumjin River, Korea. They include Metagonimus Yokogawa type (M. yokogawai) , Miyata type, and Koga type according to Saito's classification. The metacercariae were experimentally fed to rats and hamsters and a total of 1,624 Metagonimus worms were recovered from their small intestine. The number of each type was 820 for Yokogawa type, 688 for Miyata type, 46 for Koga type, and 70 undetermined. The major differential keys between Yokogawa and Miyata types were in the position of two testes, distribution of uterine tubules, and size of the eggs, and the keys between Miyata and Koga types were in the position of two testes, distribution of vitelline follicles, and size of the eggs. The validity of Miyata type as a specific level should be retained until more convincing evidences are obtained. Koga type is regarded as a synonym of M. takahashii. The present results reveal that there are 3 morphological types of Metagonimus whose larvae are encysted in the dace, T. tacganowskii, from the Sumjin River. Key words: Metagcnimus yokogawai, morphological types, rats, hamsters, dace ( Tribolodon tacxanowskii) , Sumjin Rver.

• Parasites, Hosts and Diseases
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• v.35 no.4
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• pp.223-232
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• 1997

Metagonimus miyatai n. sp. (Digenea: Heterophyidae) is described based on adult flukes collected from experimental dogs and hamsters fed with metacercariae encysted in the sweetfish, Plecoglossus altivelis, dace, Tribolodon hakonensis and T. taczanowskii, common fat-minnow. Morocco steindachneri pale chub, Zacco platypus, and dark chub, Zacco temmincki, and on those collected from naturally infected humans. The new species was morphologically compared with M. yokogawai and M. takahashii obtained from experimental animals fed with the sweetflsh and the crucian carp, Cnrossius caressius, respectively. The uterine loops of M. miyatai reached near the posterior end of the body through the space between the two testes, whereas those of M. yokogawai, occupied only the space between the acetabulum and anterior border of two testes. This uterine tubule distribution was similar to that of another closely related species, M. takahashii. However vitellaria of M. miyatai ended in front of the posterior end of the left testis, while those of M. takahcshii reached the posterior end of the left testis and ran it over. By raising M. miyatai as a new species, differentiation of M. yokogawai and M. takahashii became very clear. A key to the species of the genus Metagonimus in the Far East has been proposed.