''Gibbula tumida'' 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 ...

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 ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

, the top snails.

Description

The size of the shell varies between 4 mm and 10 mm. The small, narrowly umbilicate shell has an elevated conical shape. The color is whitish, variously strigate or maculated with brown, beneath white, unicolored or punctate with brown. The

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, somewhat turreted. The apex is acute. The sutures are impressed. The six

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 are convex, encircled by numerous, close fine striae. The periphery is obtusely angular. The base of the shell is slightly convex, and concentrically finely lirate. The

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

is coarser than upon the upper surface. The large

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 rounded-quadrate. The oblique columella is straightened and a little convex in the middle. The deep umbilicus is narrow, expanding and funnel-shaped at its opening. This species is readily recognized by the form, the whorls being a little tumid just below the sutures, and the base of the aperture is usually a little emarginate.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This species occurs in the North Atlantic Ocean and in the North Sea from

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to the

Barentz 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 ...

References

* Montagu G., 1803: ''Testacea Britannica, or natural history of British shells, marine, land and the fresh-water, including the most minute: systematically arranged and embellished with figures''; Romsey. London pp. XXXVII + 606 + 16 pl * Dillwyn L. W., 1817: ''A descriptive catalogue of Recent shells, arranged according to the Linnean method''; London Vol. 1: pp. 580 + 5 pl. . Vol. 2: pp. 581–1092 + 29 pl * Nordsieck F., 1982: ''Die europäischen Meeres-Gehäuseschnecken. 2. Auflage''; Gustav Fischer, Stuttgart 539 pp., 38 pl. * 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:Gibbula Tumida tumida Gastropods described in 1803