''Clanculus euchelioides'', common name the small 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 ...

, the top snails.Rosenberg, G. (2012). ''Clanculus euchelioides'' Tate, 1893. 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=594194 on 2012-11-23

Description

(Original description by R. Tate) The size of the shell varies between 6 mm and 9 mm. The somewhat solid shell has a turbinately conchoid shape. It is opaque, concolorous (reddish). It contains about 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. The ordinary

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 ...

whorls are separated by a canaliculate suture and are flattened posteriorly. 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 ...

is convex in the anterior-third. The base of the shell is flatly convex and falsely umbilicated. The columella enters the umbilical depression, which is shallow and moderately narrow. 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 oblique and rhomboidoval. The outer lip is slightly depressed at the suture. The outer and basal margins are thin, lirate, and iridescent within (the lirae not extending to the margin). The oblique columella is straight, rib-like, with an attenuated keel elevated into a tooth-like prominence at the base, and separated from the basal margin of the aperture by a deep gemmulated ribs of about equal magnitude. At the suture there is a double smaller rib, and there is a finer one posterior to the periphery. The transverse riblets of the penultimate whorl show increasing revolution of the whorls and become more slender and closer together. And thus the fenestrated ornament is somewhat obscured on the front part of the

. Below the periphery there are about five revolving equal-sized ribs, more or less gemmulated at the intersections of transverse sigmoidal threads, the one margining the umbilicus most conspicuously so. The umbilical wall has about five flat threads crossed by lamella-like striae. The conspicuous oblique ribbing and very wide umbilicus are characters which separate this species from the majority of its congeners.Transactions of the Royal Society of South Australia v.17 (1892-1893)
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Distribution

This marine species is endemic to Australia and occurs off

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

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 ...

and

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

References

*Tate, R. 1893. ''Some additions to the list of the Marine Gastropoda of South Australia''. Transactions of the Royal Society of South Australia 17(1): 189-202 * Tomlin, J.R. le B. 1924. ''Description of a new species of Clanculus (Clanculus gatliffi)''. Proceedings of the Malacological Society of London 16(1): 24 * Iredale, T. 1929. ''Queensland molluscan notes, No. 1''. Memoirs of the Queensland Museum 9(3): 261-297, pls 30-31 Biodiversity Heritage Library (1 publication)

World Register of Marine Species
{{Taxonbar">from=Q5125674 euchelioides Gastropods of Australia Gastropods described in 1893