Nitidotellina hachiensis n. sp. (Bivalvia: Tellinidae) from the Seto Inland Sea, between Honshū and Shikoku, western Japan

ABSTRACT

A new species of tellinid, Nitidotellina hachiensis, is described from Japan. The shell of this species is characterised by a pair of strong keels that run from the beaks to the posterior end and forms a prominent posterior notch. The recent individuals are found only in the Seto Inland Sea (Okayama, Hiroshima, Yamaguchi and Ehime prefectures), while the one fossil record so far known is from the Chibanian (middle Pleistocene) Toyohashi Formation in Aichi Prefecture, central Honshū. Living individuals are uncommon and mainly found living in sandy mud bottoms from the low tide line down to the subtidal zone in the inner parts of large bays. It can be regarded as endangered due to the recent habitat loss and water pollution of inner bay environments.

JAPANESE ABSTRACT 和文摘要

福田　宏・石川　裕・伊藤颯真・芳賀拓真: 瀬戸内海産ニッコウガイ科 (二枚貝綱) の新種 Nitidotellina hachiensis ハチザクラ.

新種 Nitidotellina hachiensis ハチザクラを記載する。この種は殻表の後背部に走る一対の稜角や後端が明瞭に凹む点が著しい特徴で, これらは同属の他種では類例が知られていない。本種の現生個体は瀬戸内海 (岡山・広島・山口・愛媛各県) のみで得られ, 更新統千葉階豊橋層の化石が愛知県でのみ報告されている。生貝は主に干潮線から潮下帯にかけての砂泥底から見出されるが, 寡産である。産出は大規模な湾奥に限られ, 近年の内湾の水質汚濁などを原因とする棲息環境の喪失により, 絶滅が危惧される稀少種と見做しうる。 ZooBank registration: http://www.zoobank.org/urn:lsid:zoobank.org:pub:98F5D4CD-C585-4AF3-BEB8-83731349DF04

KEYWORDS:

• Bivalves
• Chibanian
• conservation
• description
• endangered species
• Hachi-no-higata
• inner bay
• new species
• taxonomy
• tidal flats

Acknowledgements

We wish to thank Junlong Zhang for providing the photographs of the type material of Nitidotellina sinica. We are grateful to Yusuke Kondo, Susumu Ohtsuka and their students of Hiroshima University for their assistance in field surveys at the Hachi-no-higata Tidal Flats. Special thanks are due to Hiroshi Saito (NMNS), Masahiro Ichida (TMNH), and Yusuke Ando (MFM) for access to museum specimens. Philippe Bouchet, Pierre Lozouet and Hiroshi Saito kindly assisted in obtaining literature. Winston Ponder and Yoshimasa Hayase provided many useful comments on the manuscript.

Disclosure statement

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

Additional information

Funding

This study was partly funded by grant-in-aid from the Research Institute of Marine Invertebrates (Chūō-ku, Tōkyō) (no. Ko-29, 2014) to T.H.