Description of Two New Species of Philometra Costa, 1845 (Nematoda: Philometridae) from Marine Fishes off Japan, with Notes on Philometroides seriolae (Yamaguti, 1935)
Philometrid nematodes (Philometridae) represent a group of more than 200 species parasitic in the body cavity and various body tissues of fishes. Due to morphological and biological peculiarities, the majority of them are known only by their large females. Generally, the fauna of these parasites remains little known.
Occasional helminthological examinations of three species of marine fishes in Japan revealed two new and one insufficiently known species of these tissue-dwelling parasites. These were studied with the use of light and scanning electron microscopy.
All three nematode species are described. Philometra ostorhinchi sp. nov. (males and females) from the ovary of Ostorhinchus semilineatus (Temminck et Schlegel) (Apogonidae, Perciformes) is characterized mainly by the lengths and structure of spicules and the gubernaculum (spicules 108–120 µm long, length of the gubernaculum 78–87 µm); it is the only species of philometrids parasitic in a fish belonging to the Apogonidae. The gravid females of Philometra tenuis sp. nov. (only females available) from the head subcutaneous tissues of Conger myriaster (Brevoort) (Congridae, Anguilliformes) differ from congeners mainly in an unusual shape of the anterior oesophageal bulb. Some new data on the morphology of an insufficiently known species Philometroides seriolae (Ishii, 1931), collected from the body musculature of Seriola quinqueradiata Temminck et Schlegel (Carangidae, Perciformes), are provided; the number and arrangement of cephalic papillae in subgravid females of P. seriolae were found to be similar to those in females of the majority of other philometrid species.
The present study extends the knowledge of the species composition of philometrids parasitizing marine fishes and of the morphology of P. seriolae, the type species of Philometroides Yamaguti, 1935.
KeywordsDracunculoidea New taxa Anguilliformes Perciformes West Pacific Ocean
We thank Dr. Gen Kume, Kagoshima University, for providing Philometra ostorhinchi specimens. Thanks are also due to the Laboratory of Electron Microscopy, Institute of Parasitology, Biology Centre CAS, institution supported by the MEYS CR (LM2015062 Czech-BioImaging) for their support with obtaining scientific data presented in this paper, and to Blanka Škoríková of the same Institute for help with illustrations.
This study was partly supported by the institutional support of the Institute of Parasitology, BC AS CR, 585110/9500.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable institutional, national and international guidelines for the care and use of animals were followed.
- 1.Nagasawa K (2008) Synopsis of nematodes of the superfamilies Dracunculoidea and Anguillicoloidea parasitic in fishes and amphibians of Japan (1916–2008). Bull Biogeogr Soc Japan 63:111–124 (In Japanese, Engl summary) Google Scholar
- 2.Moravec F, Nagasawa K, Nitta M, Tawa A (2019) New records of philometrids (Nematoda: Philometridae) from marine fishes off Japan, including description of Philometra kidakoi sp. n. and Congerinema japonicum gen. et sp. n. Folia Parasitol (in press) Google Scholar
- 3.Froese R, Pauly D (eds) (2019) FishBase. World Wide Web electronic publication. http://www.fishbase.org, version 03/2019
- 5.Moravec F, Bakenhaster M, Fajer-Ávila EJ (2014) Three new gonad-infecting species of Philometra (Nematoda: Philometridae) parasitic in Lutjanus spp. (Lutjanidae) in the northern Gulf of Mexico off Florida, USA. Folia Parasitol 61:355–369. https://doi.org/10.14411/fp.2014.041 CrossRefPubMedGoogle Scholar
- 6.Moravec F, Chaabane A, Neifar L, Gey D, Justine J-L (2016) Descriptions of Philometra aenei n. sp. and P. tunisiensis n. sp. (Nematoda: Philometridae) from Epinephelus spp. off Tunisia confirm a high degree of host specificity of gonad-infecting species of Philometra Costa, 1845 in groupers (Serranidae). Syst Parasitol 93:115–128. https://doi.org/10.1007/s11230-015-9610-z CrossRefPubMedGoogle Scholar
- 7.Yamaguti S (1935) Studies on the helminth fauna of Japan. Part 9. Nematodes of fishes, 1. Jap J Zool 6:337–386Google Scholar
- 8.Yamaguti S (1941) Studies on the helminth fauna of Japan. Part 33. Nematodes of fishes, II. Jap J Zool 9:343–395Google Scholar
- 10.Moravec F, Ogawa K, Suzuki M, Miyazaki K, Donai H (2002) On two species of Philometra (Nematoda, Philometridae) from the serranid fish Epinephelus septemfasciatus. Acta Parasitol 47:34–40Google Scholar
- 13.Molin R (1859) Abhandlugen und Mittheilungen. Sitzungsber Akad Wiss Wien 38:7–38Google Scholar
- 15.Moravec F (2006) Dracunculoid and anguillicoloid nematodes parasitic in vertebrates. Academia, PragueGoogle Scholar
- 16.Quiazon KMA, Yoshinaga T, Ogawa K (2010) Taxonomical note on the redescription of Philometroides seriolae (Ishii, 1931) infecting Japanese amberjack (Seriola quinqueradiata Temminck et Schlegel, 1845) in Japan. J Trop Biol 8:29–34Google Scholar
- 17.Kuroda T, Murayama T, Imai J, Horii Y, Nawa Y (1991) The first record of Philometroides sp. vomited from a man in Japan. Jap J Parasitol 40:599–603Google Scholar
- 18.Ishii S (1931) Parasites of fishes of Japan. Biology. Iwanami Publ Comp, Tokyo 18:179–207 (In Japanese) Google Scholar
- 19.Nakajima K, Egusa S (1969) Philometroides seriolae (Ishii, 1931) Yamaguti, 1935, a large nematode infecting farmed yellowtail. Fish Pathol 3:115–117 (In Japanese) Google Scholar