''Calliostoma occidentale'',
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
the boreal topsnail, 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
Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...
, a marine
gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
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 Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
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 6 mm and 17 mm. The shell is rather small, thin, imperforate, and opalescent with a shining surface. It is strongly sculptured above with smooth, yellowish spiral ribs, narrower than their interstices, numbering 3 or 4 on each of the 7 to 8
whorl
A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs).
Whorls in nature
File:Photograph and axial plane floral ...
s. The periphery is very bluntly subangular. The base of the shell is nearly flat, with a few ribs around the axis and at the periphery, otherwise it is smooth. The acute
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 are ...
is elevated. The apical whorl is minute, smooth, and rounded. Three whorls follow which are beaded on the spiral ribs. The
sutures are impressed. The pearly
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 opt ...
is rather rounded. The narrow
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 arcuate, not dentate or truncate at its base.
Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
/ref>
Distribution
This species has a wide distribution. It occurs in European waters, the Northwest Atlantic Ocean, Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
, Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...
and in the Barents Sea
The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
at depths between 18 m and 1800 m.
References
Further reading
* Lovén, . L.1846. ''Nordens Hafs-Mollusker''. Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar 3: 134–160.
* Brunel, P., Bosse, L. & Lamarche, G. (1998). ''Catalogue of the marine invertebrates of the estuary and Gulf of St. Lawrence''. Canadian Special Publication of Fisheries and Aquatic Sciences, 126. 405 p.
* de Kluijver, M.J.; Ingalsuo, S.S.; de Bruyne, R.H. (2000). ''Macrobenthos of the North Sea D-ROM 1. Keys to Mollusca and Brachiopoda.'' World Biodiversity Database CD-ROM Series. Expert Center for Taxonomic Identification (ETI): Amsterdam, The Netherlands. . 1 cd-rom pp
* 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
* Trott, T.J. 2004. ''Cobscook Bay inventory: a historical checklist of marine invertebrates spanning 162 years''. Northeastern Naturalist (Special Issue 2): 261–324
External links
*
{{DEFAULTSORT:Calliostoma Occidentale
occidentale
Gastropods described in 1842