''Calliostoma unicum'', common name Dall's unicum top shell, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of sea snail, a marine gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Calliostomatidae Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.Gofas, S. (2013). Calliostomatidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdeta ...

. Some authors place this taxon in the subgenus ''Calliostoma (Tristichotrochus)''

Description

The height of the shell varies between 13 mm and 23 mm. The solid, conical shell is imperforate. It has seven, inflated globose whorls with a rounded periphery and a closed umbilicus. The whorls show a more or less obvious angle or carina in the middle of the upper surface. The body whorl is subangular or rounded at the periphery and convex beneath. The surface texture consists of numerous, unequal spiral striations which are beaded on the early whorls. These striations are slightly crenulated by regular incremental lines. These striations number about 9 on the penultimate whorl, 12–14 on the base. The low

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires a ...

is rather short. The acute

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex, ...

is red or purplish. The oblique, rhomboidal

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

is white and nacreous. The

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

is very much thickened within. The oblique

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

is concave above, cylindrical, and has a groove marking the place of the umbilicus. The base color is a light reddish brown with irregular maculations of darker brown above and a row of small alternating white and dark brown spots encircling the whorls. It has a brown-articulated peripheral girdle. The base of the shell is generally not marked.''Shells of the Western Pacific'' (1965) Tetsuaki Kira, Hoikusha Publishing Co., Ltd., p. 11Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This marine species is found from Central

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island se ...

, Japan southwards at 10 to 20 m depth., also off China,

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

and

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

References

External links

* {{DEFAULTSORT:Calliostoma Unicum

unicum Unicum () is a Hungarian herbal liqueur or bitters, drunk as a digestif and apéritif. The liqueur was created in 1790 and is today produced by Zwack according to a secret formula of more than forty herbs; the drink is aged in oak casks. Du ...

Gastropods described in 1860