''Calliostoma gualterianum'', common name Gualtieri's 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 ...

Description

The size of the shell varies between 10 mm and 17 mm. The imperforate, polished, solid shell has a conical-elevated shape with 9 whorls. It is yellowish-brown or olive, clouded with brown, the earlier 4 whorls dark bluish or greenish. The shell is spirally sulcate, the 2d whorl somewhat granulate. The rest of the whorls are smooth, flat, and with a narrow supra-sutural fasciole, which on the body whorl is not developed. The periphery is rounded angular. The base of the shell is smooth except for about 4 fine riblets around the axis. The

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 smooth within. The nacreous

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 a trifle swollen at its base, and either purple or whitish inside.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This species occurs in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

References

* Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213

External links

* {{DEFAULTSORT:Calliostoma Gualterianum gualterianum Gastropods described in 1848 Taxa named by Rodolfo Amando Philippi