PURPOSE: Many nematode species parasitizing marine fishes were reported from Japanese waters. However, considering the wealth of fish species in this zoogeographically interesting region and the host specificity of nematodes, the number of hitherto recorded fish nematodes probably represents only a very small part of the potential Japanese fauna of these organisms. Therefore, new data are needed to recognise the species composition of these parasites in this region. METHODS: Helminthological examinations of some marine fishes from off Japan, carried out in the years 2005-2017, revealed one new and five insufficiently known species of ascaridoid and seuratoid nematodes. These were studied with the use of light and scanning electron microscopy. RESULTS: All six nematode species recorded are described: Anisakidae: Raphidascaris (Ichthyascaris) multipapillata sp. nov. (male and females) from the intestine of Labracoglossa argenteiventris Peters (Kyphosidae) in the Sea of Japan, Raphidascaris (Ichthyascaris) sp. (third-stage larvae) probably from the digestive tract of Seriola dumerili (Risso) and S. rivoliana Valenciennes (both Carangidae) in the western North Pacific Ocean off Ishigaki-jima Island, Okinawa Prefecture, Hysterothylacium simile Li et al., 2013 (males and females) from the stomach of Lateolabrax japonicus (Cuvier) (Lateolabracidae) in the Sea of Japan, Hysterothylacium sp. 1 (female) from the pyloric caeca of Jaydia lineata (Temminck et Schlegel) (Apogonidae) in the Seto Inland Sea, Hysterothylacium sp. 2 (third- and fourth-stage larvae) from the intestine and mesentery of Etelis coruscans Valenciennes (Lutjanidae) and Pseudorhombus pentophthalmus Günther (Paralichthyidae) in the western North Pacific Ocean off Ishigaki-jima Island, Okinawa Prefecture and the Seto Inland Sea, respectively; and Cucullanidae: Cucullanus sp. (female) from the intestine of Semicossyphus reticulatus (Valenciennes) (Labridae) in the Seto Inland Sea. Raphidascaris (I.) multipapillata sp. n. differs from congeners mainly in the high number (79) of pairs of caudal papillae, spicules 402 µm long and in the structure of the male and female tail tips. Hysterothylacium simile is redescribed, being recorded from off Japan for the first time. CONCLUSIONS: In addition to the discovery of the new nematode species R. (I.) multipapillata sp. nov. and a redescription of H. simile providing some new morphological data of this parasite, the findings of all other species represent new host and geographical records. The present study extends the knowledge of the species composition and host-parasite relationships of nematodes parasitizing marine fishes.

• Klíčová slova
• Cucullanus, East Asia, Hysterothylacium, Osteichthyes, Parasitic nematode,
• MeSH
• Ascaridoidea * MeSH
• nemoci ryb * MeSH
• ryby MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Japonsko MeSH
• Tichý oceán MeSH

Here, we present the results of a taxonomic survey of the nematodes parasitizing fishes from the lagoon flats of Palmyra Atoll, Eastern Indo-Pacific. We performed quantitative parasitological surveys of 653 individual fish from each of the 44 species using the intertidal sand flats that border the atoll's lagoon. We provide morphological descriptions, prevalence, and mean intensities of the recovered seven species of adult nematode (Pulchrascaris chiloscyllii, Capillariidae gen. sp., Cucullanus bourdini, Cucullanus oceaniensis, Pseudascarophis sp., Spinitectus (Paraspinitectus) palmyraensissp. nov., Philometra pellucida) and three larval stages (Pulchrascaris sp., Hysterothylacium sp., Cucullanus sp.). We recorded: Pulchrascaris chiloscyllii from Carcharhinus melanopterus; Capillariidae gen. sp. from Chaetodon lunula, Lutjanus fulvus, and Ellochelon vaigiensis; Cucullanus bourdini from Arothron hispidus; Cucullanus oceaniensis from Abudefduf sordidus; Pseudascarophis sp. from Chaetodon auriga, Chaetodon lunula, and Mulloidichthys flavolineatus; Spinitectus (Paraspinitectus) palmyraensissp. nov. from Albula glossodonta; Philometra pellucida from Arothron hispidus; and three larval forms, Pulchrascaris sp. from Acanthurus triostegus, Acanthurus xanthopterus, Rhinecanthus aculeatus, Platybelone argalus, Carangoides ferdau, Carangoides orthogrammus, Caranx ignobilis, Caranx melampygus, Caranx papuensis, Chaetodon auriga, Chanos chanos, Amblygobius phalaena, Asterropteryx semipunctata, Valencienea sexguttata, Kyphosus cinerascens, Lutjanus fulvus, Lutjanus monostigma, Ellochelon vaigiensis, Mulloidichthys flavolineatus, Upeneus taeniopterus, Gymnothorax pictus, Abudefduf septemfasciatus, Abudefduf sordidus, and Stegastes nigricans; Hysterothylacium sp. type MD from Acanthurus triostegus, Carangoides ferdau, Chaetodon lunula, Chanos chanos, Kyphosus cinerascens, Abudefduf sordidus, and Arothron hispidus; and Cucullanus sp. from Caranx ignobilis. Spinitectus (Paraspinitectus) palmyraensissp. nov. (Cystidicolidae) is described from the intestine of roundjaw bonefish Albula glossodonta. All the nematode species reported in this study represent new geographical records. We discuss how our survey findings compare to other areas of the Indo-Pacific, and the way the relatively numerical dominance of trophically transmitted larval stages likely reflect the intact food web of Palmyra Atoll, which includes a large biomass of large-bodied top predator sharks and ray-finned fishes.

• Klíčová slova
• Cucullanus, Hysterothylacium, Paraspinitectus, Philometra, Pseudascarophis, Pulchrascaris,
• Publikační typ
• časopisecké články MeSH