The bivalve genus Sunetta Link, 1807 (Heterodonta: Veneridae) of Japan and the neighbouring waters – a taxonomic revision with the descriptions of three new species

ABSTRACT

Species of Sunetta Link, 1807 from Japan and the neighbouring regions (Korea, China and Taiwan) are revised taxonomically. Eight species of the subgenus Sunemeroe Iredale, 1930 are recognised: Sunetta beni n.sp., S. crassatelliformis Haga and H. Fukuda, n.sp., S. cumingii E.A. Smith, 1891, S. kirai Huber, 2010, S. langfordi (Habe, 1953), S. menstrualis (Menke, 1843) S. nomurai Haga and H. Fukuda, n.sp., and S. sunettina (Jousseaume, 1891). Although S. beni has long been misidentified as S. solanderii (Gray, 1825) from the Indian Ocean, it is distinguishable from all other Sunemeroe species in having a small, oval and inflated shell with a round posterior end and a broad and deeply sunken escutcheon. Sunetta crassatelliformis is a Lower Pleistocene species endemic to Japan. Another fossil species S. nomurai is known from the Pleistocene of Taiwan. Sunetta cumingii, a little-known Recent species from southwestern Japan and Taiwan, is separable from S. sunettina (= S. contempta E.A. Smith, 1891), which has often been regarded as synonymous. Amongst the six Recent species only S. sunettina is widely distributed in the Indo-West Pacific; the other five have narrower geographical ranges around Japan. Sunetta beni and S. menstrualis are thought to be threatened due to habitat loss.

和文摘要

福田　宏・石田　惣・渡部哲也・吉松定昭・芳賀拓真：日本及び近隣海域産ワスレガイ属（二枚貝綱：異歯類：マルスダレガイ科）— 3新種の記載を伴う分類学的再検討

日本とその周辺海域（韓国 , 中国 , 台湾）に産する Sunetta ワスレガイ属の種の分類学的再検討を行った。いずれも Sunemeroe 亜属に属す次の8種が認められた：Sunetta beni n.sp. ベニワスレ（新種） , S. crassatelliformis Haga and H. Fukuda, n.sp. モシオワスレ（新種・新称） , S. cumingii E.A. Smith, 1891 タイワンワスレ , S. kirai Huber, 2010 シマワスレ（イソワスレ） , S. langfordi (Habe, 1953) ランフォードワスレ（オキナワワスレ） , S. menstrualis (Menke, 1843) ワスレガイ（イイビツガイ） , S. nomurai Haga and H. Fukuda, n.sp. シチヘイワスレ（新種・新称） , 及び S. sunettina (Jousseaume, 1891) ミワスレ。ベニワスレは従来 , インド洋産 S. solanderii (Gray, 1825) に誤同定されてきたが , ベニワスレの殻は卵形で膨らみが強く , 前端・後端ともに丸みを帯び , 楯面が幅広く深い点で Sunemeroe に属す他のどの種とも異なる。モシオワスレは下部更新統の化石種で日本固有であり , 恐らくワスレガイの姉妹種である。もう一つの化石種であるシチヘイワスレは台湾の更新統から見出された。和歌山県・南西諸島と台湾等に産するタイワンワスレはこれまでミワスレの異名とされることが多く , 存在が十分に認識されてこなかったが , 独立した別種と認められる。上記現生6種のうちミワスレはインド−西太平洋に広く分布するのに対し , それ以外の5種は日本周辺の比較的狭い範囲に固有である。特にベニワスレとワスレガイは棲息地の縮小によって危機的状況にあると考えられる。

ZooBank registration: http://www.zoobank.org/urn:lsid:zoobank.org:pub:B563A577-077D-46F0-BB81-2E680EAF41E8

KEYWORDS:

• Distribution
• endangered species
• fossil
• morphology
• Plio-Pleistocene
• sandy bottom
• shallow sea
• Sunemeroe
• Sunettinae
• taxonomy

Acknowledgements

For providing loans and/or assistance to our examinations of museum specimens, we thank Shinji Eda (KURA), Kiyoshi Hagiwara (YCM), Kazunori Hasegawa (NSMT), Rei Hirano (RFM), Masahiro Ichida (TMNH), Ken-ichirō Ishii (KI), Tomoki Kase (NMNS), Yuri Kimura (NMNS), Yasuo Kondō (Kōchi University), Hiromune Mitsuhashi (MNHAH), Ken’ichi Nakao (TKPM), Jun Nemoto (IGPS), Hiroshi Saitō (NSMT), Takehiro Satō (KPMNH), Hayato Takeshita (MZS), Shinya Umemura (FMNH), Kazutaka Yamada (TKPM), Yūsuke Yamana (WMNH), Tasuku Yoshioka (TSM), and Masatsuna Yotsuyanagi (Noto Satoyama Satoumi Museum, Nanao, Ishikawa). Specimens of Sunetta beni from Kagawa and Okayama prefectures were obtained through the courtesy of Masanori Takahashi (Fisheries Resources Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency), and Noriko Akai and Kei Takasago (Kagawa Prefectural Fisheries Experimental Station). We are also grateful to Kazutaka Amano, Katsuyoshi Baba, Don Colgan, Yoshimasa Hayase, Shigeo Higuchi, Shigeo Hori, Hitoshi Ikeda, Yoshiaki Ishida, Hiroshi Ishikawa, Kunitsugu Kawabe, Shōichi Kimura, Hirofumi Kubo, Yasuhiro Kuwahara, Ryūichi Majima, Bruce Marshall, Wataru Mukaimine, Hideo Nagato, Takami Nobuhara, André Sartori, Doris Shearman, Masanori Taru, and Yūta Yamaoka for their helpful assistances or comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was partly supported by an internal grant from NMNS [grant number #3211] and the Japan Society for the Promotion of Science KAKENHI [grant number 17H07386] to T.H.