Acteocina exilis (Dunker, 1860)

Description

A minute snail with a thin, polished white shell about 6 mm long. The shell is elongate-cylindrical with acutely angulated shoulders and deeply canaliculated (groove-like) sutures; the protoconch is sinistrally coiled and protrudes from the apex. Weak spiral grooves run across the base, and the columella bears a weak fold.

Distribution

Habe (1961) recorded the species from Honshu to Kyushu in 5–50 m depth on sandy mud bottoms. Okutani (ed.) 2000 (Marine Mollusks in Japan) extended the recorded range from Sanriku on the Pacific coast and the Oga Peninsula on the Japan Sea coast southward to Kyushu and the South China Sea, on fine sand bottoms in 5–115 m depth.

Etymology

The specific epithet exilis is a Latin adjective meaning "slender" or "thin", referring to the elongate shell.

Remarks

Originally described as Bulla exilis Dunker, 1860; treated here under the combination Acteocina exilis.

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References

• Bulla exilis n. sp., Dunker W. (1860). Neue japanische Mollusken. Malakozoologische Blätter. 6: 221-240. [Published January 1860]
• ヨワコメツブ Acteocina (Tornatina) exilis (DUNKER), 波部忠重. (1961). 続原色日本貝類図鑑. 保育社, 大阪. xii + 183 + 42 pp., 66 pls. [Habe T. (1961). Coloured illustrations of the shells of Japan (II). Hoikusha, Osaka.]
• ヨワコメツブガイ Acteocina exilis (Dunker, 1859), 奥谷喬司. (2000). 日本近海産貝類図鑑. 東海大学出版会.
• ヨワコメツブガイ, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.