''Gibbula multicolor'',

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 multicoloured topshell, 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 height of the shell attains 6½ mm, its diameter 7 mm. The small, narrowly perforated shell has a conoidal shape with five

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 first is whitish-rosy, the following white, with reddish flammules and spots of green and bluish, especially at the ridges. The surface of the whorls is marked with very fine spiral and vertical striae, and 2 elevated carinae. The

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

contains three keels. The base of the shell is red with a spiral series of green streaks, concentrically striate. 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 opt ...

is suboval and smooth within. The columella is white. (Description of ''Gibbula fucata'') The height of the shell attains 5.6 mm, its diameter 7.3 mm. The elevated shell has a helicoid shape. Its apex is red, the rest variously spotted, streaked and blotched with Indian red, pale yellow, light green and brown. The 2½ nuclear

s are well rounded and smooth. The postnuclear whorls are marked by four, very strong, rounded, equal, and equally spaced, spiral cords, of which the first is at the summit and the fourth at the periphery. On the last turn the cord at the summit becomes obsolete. In addition to the spiral

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 ...

the whorls are marked by very retractively slanting, closely spaced lines of growth. The periphery of the

is rendered decidedly angulated by the spiral cord. The base of the shell is short, well rounded, marked on the posterior fourth by six, narrow, flattened, spiral bands and between these and the umbilical chink by seven additional bands of about double the width of the former. The umbilicus is covered with a white callus. The

is subcircular and very oblique. The outer lip is thin at the edge and thick within. The columella is strong and decidedly curved. The parietal wall is covered by a moderately thick callus. (Description as ''Stomatella biporcata'') The shell is turbinate and subdepressed. Its color is red and white, obscurely variegated. It is transversely sulcate. The acuminate

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 ...

contains four

s, the last with two prominent ridges. The subquadrate

is pearly within. The inner lip is nearly straight. The outer lip is bi-angulate in the middle. The umbilicus is covered by a callus. This is a small red species, with two rounded ridges on the

and with a subquadrate aperture.H.A. Pilsbry (1890) Manual of Conchology XII; Academy of Natural Sciences, Philadelphia, 1890
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Distribution

This marine species occurs off the southern coast of

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

and off

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

References

* Kilburn, R.N. & Rippey, E. (1982) ''Sea Shells of Southern Africa''. Macmillan South Africa, Johannesburg, xi + 249 pp. page(s): 41 * Steyn, D.G. & Lussi, M. (1998) ''Marine Shells of South Africa. An Illustrated Collector’s Guide to Beached Shells''. Ekogilde Publishers, Hartebeespoort, South Africa, ii + 264 pp. page(s): 20 * Adams, A. 1850. ''An arrangement of Stomatellidae, including the characters of a new genus Cumingia, with some additional generic characters.'' Proceedings of the Zoological Society of London 1850(18): 29–40, pl. 8 * Hedley, C. 1907. ''The Mollusca of Mast Head Reef, Capricorn Group, Queensland, part II.'' Proceedings of the Linnean Society of New South Wales 32: 476–513, pls 16-21 * Tomlin, J.R. le B. 1921. ''Six new marine shells from South Africa.'' Journal of Conchology 16: 215–217, pl. 8
Branch, G.M. et al. (2002). ''Two Oceans''. 5th impression. David Philip, Cate Town & Johannesburg

Herbert D.G. (2015). ''An annotated catalogue and bibliography of the taxonomy, synonymy and distribution of the Recent Vetigastropoda of South Africa (Mollusca)''. Zootaxa. 4049(1): 1–98

External links

Gastropods.com: ''Gibbula multicolor''$
{{DEFAULTSORT:Gibbula Multicolor

multicolor Multicolor is a subtractive two-color motion picture process. Multicolor, introduced to the motion picture industry in 1929, was based on the earlier Prizma Color process, and was the forerunner of Cinecolor. For a Multicolor film, a scen ...

Gastropods described in 1848