Marine Biodiversity

, Volume 49, Issue 1, pp 405–413 | Cite as

The distribution of reef-dwelling Waminoa flatworms in bays and on capes of Okinawa Island

  • Piera BiondiEmail author
  • Giovanni D. Masucci
  • Shiori Kunihiro
  • James D. Reimer
Original Paper


Waminoa spp. are acoel worms living on the surface of anthozoans. Despite being potential parasites, there is still not much information available regarding the genus’ distribution or host selectivity. The aim of this study was to evaluate the distribution and occurrence of Waminoa on coral reefs along the west coast of Okinawa Main Island (26.5° N, 127.9° E) in southern Japan, comparing sites located on capes with sites located in bays and identifying associated hosts. Scuba surveys were conducted along eight coral reef sites on the west coast of the island, between June and October 2016. Seven out of eight sites showed the presence of Waminoa. Occurrence and associated hosts varied considerably from site to site, and between sites located within bays and those at capes facing the open ocean. Waminoa individuals were significantly more abundant close to the sandy bottom at the lower end of the reef slopes and were always absent in the shallowest 5 m of every site. Waminoa coverage varied depending on the host anthozoan species. No significant differences in coverage were observed within the same host species at different sites. Thus, in Okinawa, the distribution of Waminoa on coral reefs is not random, but has patterns specific to certain anthozoan host species, with the highest occurrences within 10 m in depth from the sandy bottom areas of reefs.


Acoela Biodiversity Ryukyus Indo-Pacific Epibionts Palythoa heliodiscus 



The authors would like to thank Dr. Bert W. Hoeksema (Naturalis) for his help on coral species identification, Wee Hin Boo (U. Ryukyus) for his comments on earlier versions of this manuscript, and Noorin Najimi Nawi (U. Ryukyus) for help in the field work. This study was partially financially supported by the Campus World scholarship program from Marche Polytechnic University, Ancona, Italy. The research was financially supported by the Sasakawa Scientific Research Grant from the Japan Science Society. The funding sources had no involvement in the study design, data collection and analyses, or writing of the manuscript. No permits were required for all observational studies in this work. Comments by three anonymous reviewers improved this paper.


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Copyright information

© Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany, part of Springer Nature 2017

Authors and Affiliations

  1. 1.Molecular Invertebrate Systematics and Ecology Laboratory, Graduate School of Engineering and ScienceUniversity of the RyukyusOkinawaJapan
  2. 2.Tropical Biosphere Research CenterUniversity of the RyukyusOkinawaJapan

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