''Callistele calliston'', common name the beautiful 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 ...

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 Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 ...

(unassigned to a subfamily).Rosenberg, G. (2012). ''Callistele calliston'' (Verco, 1905). Accessed through:

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

at http://www.marinespecies.org/aphia.php?p=taxdetails&id=580405 on 2012-12-07

Description

(Original description Jos. C. Verco) The height of the shell attains 12 mm. The thin shell has a conical shape. 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 ...

consists of nine

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, including two smooth apical turns. The whorls are straight-sloping, with crowded spiral lirae, about 24 on the penultimate. They are crossed by oblique crowded accremental striae, producing sublenticular pitting. The suture is linear, immediately beneath the prominent peripheral cord which gradates the spire. 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 a suture that is slightly descending at 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 ...

. It has about 24 spiral threadlets. It is crowded with fine sinuous oblique accremental striae. The periphery is acutely angular, with a projecting rounded carina, spirally closely engraved on its upper surface andaxially crossed by rounded striae. These are much more distant than the accremental striae, provided at somewhat irregular intervals with 16 rounded invalid tubercles. The base of the shell is very flatly rounded with 7 concentric narrow lirae, the inner 4 closer than the rest, which are separated by 4 to 6 interlirate striae. The umbilicus is narrow, minutely axially incised. The aperture is oblique and roundly quadrate. The outer lip is slightly convex, thin, and smooth within The margin is sinuously convex below the suture, and concave towards the periphery. The basal lip is convex, slightly effuse, and smooth within. The upper third of the columella is concave, the rest is straight, and obliquely truncate below. The callus at the base partly borders the umbilicus and is attached to the columella along a vertical groove. The shell is purple-brown, with somewhat oblique, axial, creamy, rhomboidal flames, extending from suture to suture, and nearly equalling the foundation colour in area. On the peripheral carina, and hence above the sutures, they are replaced by two or three creamy spots, while two or three less marked white spots occupy the intervals, and thus pick out the tubercles of the carina. Every whorl is encircled by four articulated colour bands, which in the white areas are of a more opaque white than the rest of these areas, and extend slightly beyond them, and are crossed by narrow vertical or oblique red lines, while in the purple areas they are of a deeper purple tint, and are crossed by narrow axial white lines. The base is of a lighter tint, the outer 6 cinguli of a rose pink, minutely dotted with creamy white. The columella and umbilicus are white, bordered outside with green, which tints the inner two basal cinguli, and curls around the columella into the throat. The inner edge of the outer lip is golden-brown and white, interior shining and nacreous. The operculum is horny multispiral with a central nucleus. Aradial cellular fringe-like film extends over the inner three-fourths of each spiral. The formula of the

radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

is ~ .1.5. 1.5.1. ~. The central rachidian is heart-shaped, narrow free end surmounted by small, slightly serrated denticle. The other rachidians have trilobed cusps, which gradually enlarge outwards. There is a single lateral with one cusp trilobed at its base. The many marginals are unicuspidate, and not serrated. JC. Verco, Notes on South Australian Marine Mollusca, with descriptions of new species - part II; Transactions and proceedings and report of the Royal Society of South Australia, v. 29, 1905
(described as ''Astele calliston'')

Distribution

This marine species occurs off

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

References

* Cotton, B.C. 1959. ''South Australian Mollusca. Archaeogastropoda''. Handbook of the Flora and Fauna of South Australia. Adelaide : South Australian Government Printer 449 pp * Wilson, B. 1993. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp.

External links

To Biodiversity Heritage Library (2 publications)

To World Register of Marine Species
{{Taxonbar, from=Q4810599 calliston Gastropods described in 1905