Kazuya Nagasawa

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A new species of parasitic copepod, Choniomyzon inflatus n. sp., is described based on specimens collected from the external egg masses of the smooth fan lobster Ibacus novemdentatus Gibbes captured in the North Pacific Ocean off Ainan, Ehime Prefecture, western Japan. The new species differs from its congeners in having a globular to ovoid prosome, in(More)
A new species of copepod, Sarcotretes umitakaesp. n., of the siphonostomatoid family Pennellidae is described based on female specimens from the rattail Coelorinchus jordani Smith and Pope (Actinopterygii: Gadiformes: Macrouridae) caught in the East China Sea. This species is characterized by exhibiting the following characters: the large proboscis projects(More)
The continental origins of chinook salmon (Oncorhynchus tshawytscha) in the North Pacific Ocean and Bering Sea were estimated by using two freshwater parasites (Myxobolus arcticus and M. kisutchl) as biological tags. The parasite survey of adult chinook salmon from major spawning rivers in North America and Kamchatka indicated that M. arcticus was commonly(More)
Four new species of splanchnotrophid copepods are described based on specimens collected from 5 species of doridacean nudibranchs from coastal waters of Japan. They belong to 3 genera, one of which, Majimun gen. n., is new. The parasites and their hosts are as follows: Ceratosomicola japonicasp. n. ex Hypselodoris festiva (A. Adams); Splanchnotrophus(More)
During the 1980s and 1990s, scientific research cruises were conducted in both the eastern and western boundary regions of the North Pacific Ocean. The main purpose of these cruises was to examine the abundance and distribution patterns of juvenile salmon in coastal waters. These studies created one of the most extensive databases ever collected on the(More)
A new species of the monotypic genus Leposphilus Hesse, 1866 (Cyclopoida: Philichthyidae), Leposphilus vogti n. sp., is described based on adult female and male specimens from the interorbital canals of Micropogonias furnieri (Desmarest) (Sciaenidae) in Sepetiba Bay, State of Rio de Janeiro, Brazil. The new species differs from its only congener, L. labrei(More)
The Taeniacanthus balistae species group is characterized by two displaced elements on an outwardly curved and elongated terminal exopodal segment of leg 4. Members of this group parasitize tetraodontiform fishes. The group is reviewed herein based on both new material collected from tetraodontiform fishes and re-examination of voucher specimens housed at(More)
Seasonal changes in population structure of a trophically transmitted parasite Heliconema anguillae (Nematoda: Physalopteridae) were examined in Japanese eels Anguilla japonica caught from a small cove in Ehime Prefecture, western Japan. Demographic classification of the samples from May 2008 to March 2009 showed that the nematode infrapopulations in host(More)