''Clanculus atypicus'' 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 ...

, the top snails.Rosenberg, G. (2012). ''Clanculus atypicus'' Iredale, 1912. 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=592809 on 2012-11-23

Description

(Original description by

Tom Iredale Tom Iredale (24 March 1880 – 12 April 1972) was an English-born ornithologist and malacologist who had a long association with Australia, where he lived for most of his life. He was an Autodidacticism, autodidact who never went to university ...

) The small, solid, umbilicate shell has a depressedly globose shape with 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. Its periphery is rounded, and its base flattened. The colour of the shell is dark greyish-brown, painted obliquely with yellow or fawn. Its

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 fine spiral threads of varying strengths, about eighteen major ones on 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 preceding whorl shows six major threads only. The axial sculpture is represented by very fine close lines. The suture is deep, channelled, bounded by a row of nodules. 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 subquadrate. The outer lip is slightly crenulate and recurved. The deep umbilicus is surrounded by a noduled callused rim, the callus extending to meet the outer lip. The columella is obliquely inserted in the umbilicus, with a small nodule at each end. The operculum is circular, horny, thin, multispiral, with a central nucleus.Proceedings of the Malacological Society of London v. 10 (1912-1913)
/ref>

Distribution

This marine species is endemic to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, occurring off the Kermadec Islands.

References

* Iredale T. (1912). ''New generic names and new species of marine mollusca''. Proceedings of the Zoological Society of London (1912) 1: 217-228

External links

Biodiversity Heritage Library (5 publications)

World Register of Marine Species
{{Taxonbar, from=Q3732709 atypicus Gastropods of New Zealand Gastropods described in 1912