Some trematodes of freshwater fishes from North Vietnam with a list of recorded endohelminths by fish hosts

Abstract

The present paper comprises a systematic survey of trematodes collected from 12 species of freshwater fishes from North Vietnam (the Red River near Hanoi). Altogether 16 trematode species (14 adults and 2 juvenile forms) have been recorded. These include: Amurotrema dombrowskajae, Platycladorchis microacetabularis, P. macroacetabularis, Neocladorchis multilobularis, Carassotrema koreanum, Azygia hwangtsiyui, Phyllodistomum clariasi, Phyllodistomum sp., Orientocreadium batrachoides, Masenia collata, Bucephalopsis ozakii, Dollfustrema bagarii sp. n., Prosorhynchus vietnamensis sp. n., Prosorhynchus sp. juv., Metadena bagarii sp. n., and Isoparorchis hypselobagri juv. Except for the first four named species, all the trematodes are briefly described and illustrated and some problems concerning their taxonomy and geographical distribution are discussed. D. bagarii sp. n. from Bagarius bagarius (catfish) is characterized mainly by location of the mouth opening in anterior half of body, extension of the uterus anteriorly not surpassing vitellaria, number of spines (about 60) on the rhynchus, and by other features. Characteristic features of P. vietnamensis sp. n. (host B. bagarius) are the structure and shape of the rhynchus, equatorial situation of vitellaria, postequatorial distribution of gonads and mouth opening, extension of the uterus, and body measurements, whereas those of M. bagarii sp. n. (host B. bagarius) include the shape (spherical) of the ovary, extent of caeca (slightly surpassing testes) and body measurements. Carassotrema ginezinskajae Kulakova et Ha Ky, 1976 is considered a junior synonym of C. koreanum Park, 1938. Eight species have not yet been reported from Vietnam. The findings include several new host records.