Pigmentation patterns are useful for species identification of third-stage larvae of gnathiids (Crustacea: Isopoda) parasitising coastal elasmobranchs in southern Japan
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Previous studies from southern Japan reported larval stages of eight gnathiid isopod species parasitising coastal elasmobranchs. Since gnathiid larvae of these different species closely resembled each other, it was necessary to obtain specimens of free-living adult males for identification to the species level. This was achieved by allowing larvae of the final stage to moult into adult males. From these males, specimens of a species new to science were discovered and described here as Gnathia rufescens n. sp. The main differentiating characteristics of G. rufescens n. sp. are: (i) the apex of pleotelson is oval shaped; (ii) the dorsal sulcus is wide in the posterior part; and (iii) the article 3 of the pylopod is not reduced in the male. Additionally, this paper summarises the specific pigmentation patterns of third-stage larvae of the new species and eight previously described species. Furthermore, host records and host use by the gnathiids were summarised based on data from 158 hosts and over 4,500 gnathiid samples; these are discussed with a focus on host-specificity of the nine gnathiid species studied.
KeywordsDistal Margin Plumose Seta Pigmentation Pattern Disk Width Internal Margin
Part of the material examined in this study was collected during the KUMEJIMA 2009 Expedition organized by the Transdisciplinary Research Organization for Subtropical and Island Studies of the University of the Ryukyus, the Center for Marine Bioscience & Biotechnology of the National Taiwan Ocean University, the Raffles Museum of Biodiversity Research of the National University of Singapore, and the Biodiversity Research Center of the Academia Sinica. The expedition operated under a permit granted to Dr. T. Naruse by the Okinawa Prefectural Governor and the Kumejima Fisheries Cooperative. This study was partly supported by a Grant-in-Aid JSPS Fellows (No. 23–527). I would like to thank two anonymous reviewers for their valuable comments.
- Carpenter, K. E., & Niem, V. H. (1998). Volume 2. Cephalopods, crustaceans, holothurians and sharks. In: FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Rome: FAO, pp. 687–1396.Google Scholar
- Carpenter, K. E., & Niem, V. H. (1999). Volume 3. Batoid fishes, chimaeras and bony fishes part 1 (Elopudae and Linophrynidae). In: FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Rome: FAO, pp. 1397–2068.Google Scholar
- Curtis, L. M., Grutter, A. S., Smit, N. J., & Davies, A. J. (2013). Gnathia aureamaculosa, a likely definitive host of Haemogregarina balistapi and potential vector for Haemogregarina bigemina between fishes of the Great Barrier Reef, Australia. International Journal for Parasitology, 43, 361–370.CrossRefPubMedGoogle Scholar
- Farquharson, C., Smit, N. J., & Sikkel O. C. (2012). Gnathia marleyi sp. nov. (Crustacea, Isopoda, Gnathiidae) from the Eastern Caribbean. Zootaxa, 3381, 47–61.Google Scholar
- Ferreira, M. L., Smit, M. J., & Davies, A. J. (2010). Gnathia grutterae sp. nov. (Crustacea, Isopoda, Gnathiidae) pasasitizing representatives of the Balistidae, Labridae and Tetraodontidae from Lizard Island, Great Barrier Reef, Australia. Zootaxa, 2718, 39–50.Google Scholar
- Froese, R., & Pauly, D. (2012). Fishbase. World wide web electronic publication. www.fishbase.org, version (10/2012). Accessed 1 December 2012.
- Grutter, A. S., Rumney, J. G., Sinclair-Taylor, T., Waldie, P., & Franklin, C. E. (2011). Fish mucus cocoons: the ‘mosquito nets’ of the sea. Biology Letters, 7, 292–294.Google Scholar
- Hadfield, K. A., Smit, N. J., & Avenant-Oldewage, A. (2008). Gnathia pilosus sp. nov. (Crustacea, Isopoda, Gnathiidae) from the East Coast of South Africa. Zootaxa, 1894, 23–41.Google Scholar
- Honma, Y., & Chiba, A. (1991). Pathological changes in the branchial chamber wall of stingrays, Dasyatis spp., associated with the presence of juvenile gnathiids (Isopoda, Crustacea). Gyobyo Kenkyu, 26, 9–16.Google Scholar
- Honma, Y., Tsunaki, S., Chiba, A., & Ho, J.-S. (1991). Histological studies on the juvenile gnathiid (Isopoda, Crustacea) parasitic on the branchial chamber wall of the stingray Dasyatis akajei in the Sea of Japan. Report on Sado Marine Biological Station, Niigata University, 21, 37–47.Google Scholar
- McKiernan, J. P., Grutter, A. S., & Davies, A. J. (2005). Reproductive and feeding ecology of parasitic gnathiid isopods of epaulette sharks (Hemiscyllium ocellatum) with consideration of their role in the transmission of a haemogregarine. International Journal for Parasitology, 35, 19–27.CrossRefPubMedGoogle Scholar
- Monod, T. (1926). Les Gnathiidae. Essai monographique (morphologie, biologie, systématique). Mémories de la Société des Sciences Naturelles du Maroc, 13, 1–667.Google Scholar
- Nakabo, T. (1993). [Fishes of Japan with pictorial keys to the species.] Tokyo: Tokai University Press, 1,474 pp (In Japanese).Google Scholar
- Nunomura N., & Honma Y. (2004). Gnathia capillata, a new species of the genus Gnathia (Crustacea, Isopoda) from Sado Island, the Sea of Japan. Contribution from the Biological Laboratory, Kyoto University, 29, 343–349.Google Scholar
- Nunomura, N. (1981). Gnathia sugashimaensis, a new gnathiid isopod from Sugashima, Ise Bay, Central Japan. Contributions from the Toyama Science Museum, 3, 19–24.Google Scholar
- Nunomura, N. (1998). A new species of the gnathiid isopod crustacean from the Sea off Sanriku, northern Japan. Contributions from the Toyama Science Museum, 21, 55–60.Google Scholar
- Nunomura, N. (2012). Marine isopod crustaceans collected from Shijiki Bay, western Japan, (2) Gnathiidae. Contributions from the Toyama Science Museum, 35, 57–76.Google Scholar
- Ota, Y. (2011). A new species of the gnathiid isopod, Gnathia teruyukiae (Crustacea: Malacostraca), from Japan, parasitizing elasmobranch fish. Bulletin of the National Museum of Nature and Science, Series A, Suppl. 5, 41–51.Google Scholar
- Ota, Y. (2012). Gnathiidae from Kumejima island in the Ryukyu Archipelago, southwestern Japan, with description of three new species (Crustacea: Isopoda). Zootaxa, 3367, 79–94.Google Scholar
- Ota, Y. & Hirose, E. (2009a). Description of Gnathia maculosa and a new record of Gnathia trimaculata (Crustacea, Isopoda, Gnathiidae), ectoparasites of elasmobranchs from Okinawan coastal waters. Zootaxa, 2114, 50–60.Google Scholar
- Ota, Y. & Hirose, E. (2009b). Gnathia nubila n. sp. and a new record of Gnathia grandilaris (Crustacea, Isopoda, Gnathiidae) that parasitizes elasmobranchs from Okinawan coastal waters, Japan. Zootaxa, 2238, 43–55.Google Scholar
- Patarnello, P. P., Fioravanti, M. L., Caggiano, M., & Restani, R. (1995). Infestazione da Gnathiidae (Crustacea: Isopoda) in Pargus major. Bollettino Societa Italiana di Patologia Ittica, 17, 32–36.Google Scholar
- Schotte, M., Boyko, C., Bruce, N. L., Poore, G. C. B., Taiti, S. & Wilson, G. D. F. (2008 onwards). Isopoda statistics. World Marine, Freshwater and Terrestrial Isopod Crustaceans. http://www.marinespecies.org/isopoda. Accessed 1 Dec. 2012.
- Smit, N. J., Van As, J. G., & Basson, L. (1999). A redescription of the adult male and praniza of Gnathia africana Barnard, 1914 (Crustacea, Isopoda, Gnathiidae) from southern Africa. Folia Parasitologica, 46, 229–240.Google Scholar
- Svavarsson, J., & Bruce, N. L. (2012). New and little-known gnathiid isopod crustaceans (Cymothoida) from the northern Great Barrier Reef and the Coral Sea. Zootaxa, 3380, 1–33.Google Scholar
- Tanaka, K. (2004). A new species of Gnathia (Isopoda: Cymothoida: Gnathiidae) from Ishigaki Island, the Ryukyus, southwestern Japan. Crustacean Research, 33, 51–60.Google Scholar
- Yoshida, Y. (1988). [Reports on ectoparasites of gnathiids occurred on juvenile bastard halibut Paralichthys olivaceus.] Annual Report of the Aomori Prefectural Inland Water Fisheries. Experimental Station 1986, pp. 131–135 (in Japanese).Google Scholar