Records of the giant spoon worm Ikeda taenioides (Annelida: Echiura: Ikedidae) from the Kii Peninsula, the Sea of Japan, and Amami-Oshima Island

: Ikeda taenioides （ Ikeda, 1904 ） （ Annelida: Echiura: Ikedidae ） is the largest spoon worm in the world and has been recorded only from Japanese coasts. This species was described by Ikeda in 1904 and then collected from various local-ities in Japan by the middle of the 20th century. However, this species has dramatically decreased in number because of habi-tat destruction and human activities; it has not been recorded recently, except for in Kagoshima Bay, the Tohoku district, and the Seto Inland Sea. Thus, a field survey is required to reevaluate its current distribution. In this study, we collected probos cises of I. taeniodes using a yabby pump in a mud flat in Tanabe Bay （ Wakayama Prefecture ） located in the southwestern part of the Kii Peninsula, Japan. We also sampled a proboscis of I. taenioides using a Smith-McIntyre grab sampler at a depth of 25 m in the mouth of Maizuru Bay （ Kyoto Prefecture ） , the Sea of Japan. The former and latter samples update the records of I. taenioides from the Kii Peninsula and Sea of Japan for the first time in 70 and 51 years, respectively. Moreover, we also observed a proboscis, most likely I. taeniodes , coming out of a burrow entrance at a water depth of 21 m off Kuninao, Ama-mi-Oshima Island （ Kagoshima Prefecture ） , Japan, which may update the southern limit of the distribution of this species. The specimens from Kii Peninsula and Maizuru Bay were genetically identified to be I. taenioides by comparing with those from the Seto Inland Sea and Tohoku district by a COI marker. Our findings suggest that I. taenioides may be still broadly distributed along the coasts of Japanese Islands, from Mutsu to Ryukyu Islands, both in the Pacific and Sea of Japan sides.