''Carinastele niceterium'' 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 ...

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=taxdetail ...

Description

(Original description by Hedley & May) The height of the shell attains 7 mm. The thin, imperforate shell has a conical-turbinate shape. Its colour uniform is pale cream and of silken lustre. The shell contains 5½

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 ...

, including a small pointed obliquely set protoconch of 1½ whorl.

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 ...

: prominent spiral keels, three to the penultimate, ten to 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 ...

, successively diminishing from the suture to the base. They are undercut below the narrow summit, parted by much broader flat interstices. These keels, apparently folds in the shell substance, are microscopically beaded by fine radial striae, represented in the interstices as hair lines. The

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

does not share the adult sculpture, but is minutely malleated. The oblique

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 subcircular. The glazed columella is arched, running out to a spur. The outer lip is unfinished, the ends of the ribs projecting beyond the interstices like claws. In the throat a furrow corresponds to each external keel.Hedley & May (1908), Mollusca from one hundred fathoms, seven miles east of Cape Pillar, Tasmania; Records of the Australian Museum v. 7 (1908)

Distribution

References

* Marshall B.A. (1988) ''Thysanodontinae: A new subfamily of the Trochidae (Gastropoda).'' Journal of Molluscan Studies 54: 215–229 niceterium Gastropods described in 1908 {{Calliostomatidae-stub