Retusa succincta (A. Adams, 1862)

Description

A minute barrel-shaped cephalaspidean reaching just a few millimetres in shell length. Shell thin, cylindrical, white, sculpted with longitudinal striations and crossed by indistinct pale bands; spire whorls visible but sunken, vertex truncate. Aperture linear, narrowed at the middle and dilated anteriorly; columellar lip with an obsolete plication. Burrows in sandy mud using the head-shield.

Distribution

Seas of China and Japan. The type localities are Tsushima (16 fathoms) and Awashima (low water).

Etymology

The specific epithet succincta is the Latin feminine of succinctus, "girded" or "tucked up" (from succingere, "to gird below"), in reference to the constricted, girdle-like contour of the shell.

Remarks

Originally described as Tornatina succincta in Adams' "On some new species of Cylichnidae, Bullidae, and Philinidae, from the Seas of China and Japan" (Annals and Magazine of Natural History, ser. 3, 9: 152, 1862). Adams compared the species directly to Tornatina truncata (J. Adams), noting his species as more elongate and narrower with indistinct pale bands. Junior synonyms include Retusa cucurbitina Yokoyama, 1927, Retusa percucurbitina Nomura, 1939, and Retusa siogamaensis Nomura, 1939.

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References

• Tornatina succincta, Adams A. (1862). On some new species of Cylichnidae, Bullidae, and Philinidae, from the Seas of China and Japan. Annals and Magazine of Natural History, series 3, 9: 150-161.
• ヘコミツララガイ Retusa (Coleophysis) succincta A. Adams, 1862, 奥谷喬司. (2000). 日本近海産貝類図鑑. 東海大学出版会.