''Clanculus robertsi'' 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.H. Pilsbry, Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Description

The height of the shell attains 12.5 mm, its diameter 13 mm. This form is similar in color-pattern and sculpture to '' Clanculus clanguloides'' Wood, 1828, but differs notably in the greater altitude, the more turbinate form, and its greater development of the teeth. In these characters it is like '' Clanculus stigmatarius'' A. Adams, 1853, which is, however, quite different in coloration. 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 conical. The apex is tinged with orange. The upper

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 nearly flat, separated by a linear suture, which becomes more deeply impressed at 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 ...

. The body whorl is slightly convex, rounded at the periphery, deeply deflected and flattened toward 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 ...

. The base of the shell is rather flattened, about the same as in ''Clanculus clanguloides''. 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 ...

consists of spiral series of closely set rounded granules, the series or cinguli a little separated on the upper surface, closer beneath. These number 17 or 18 upon the body whorl, the 7th being upon the periphery, just as in ''Clanculus clanguloides''. The interstices between lirae are finely obliquely and spirally striate, the spiral striae often a little difficult to distinguish. This gives the interstices at times a granulate appearance under the lens. The aperture is nearly horizontal, tetragonal. The superior lip is straightened, bearing a very large subbifid squarish tubercle in the middle. The place of the periphery is marked inside by an entering lamellar fold. The basal margin is curved, slightly expanded, bearing two or three fold-like denticles inside. Its edge is minutely denticulate. The oblique columella deeply enters the narrow umbilicus and is inserted in the center of the axis, slightly dentate above, bearing a narrow tooth below the middle, and terminating in a large, heavy bi- or triplicate tooth. The parietal area is covered by a white callus bearing numerous wrinkles, one or two of which enter the aperture. The umbilicus is surrounded by a radiately strongly plicate callus. The coloration is the same as in ''Clanculus clanguloides''. (described as ''Trochus robertsi'') On old specimens, the compression and deflection of the body whorl gives the shell a bullet shape.

Distribution

This marine species occurs in the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

References

External links

ANSP Malacology Collection
{{DEFAULTSORT:Clanculus Robertsi robertsi Gastropods described in 1889