''Cyclostrema subexcavatum'' 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 ...

Liotiidae Liotiidae is a family of small sea snails, marine gastropod mollusks in the clade Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Gofas, S. (2013). Liotiidae Gray, 1850. Accessed through: World Register of ...

.Rosenberg, G. (2012). ''Cyclostrema subexcavatum''. 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=532707 on 2012-12-03

Description

(Original description by G.W. Tryon) The height of the shell attains 2.2 mm. The umbilicus is wide, perspective and shallow. The shell is whitish under a yellowish brown, membraneous

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...

. 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 scarcely raised. The 4

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 increase rather slowly until the last, which is rather large. The suture is broadly, angularly impressed. A little below the suture there is a bluntly angulated spiral keel. And on the middle of the base, towards 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 ...

there is another keel. The thin peristome is simple.G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia
/ref>

Distribution

This marine species occurs off Puerto Rico at a depth of about 700 m.

References

* Watson, R. B. 1886. ''Report on the Scaphopoda and Gasteropoda collected by H.M.S. Challenger during the years 1873-1876''. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology 15(2): i-v, 1-680, 692-756, 50 pls. Her Majesty's Government: London

External links

Biodiversity Heritage Library (1 publication)

Encyclopedia of Life

World Register of Marine Species
{{Taxonbar, from=Q13583776 subexcavatum Gastropods described in 1888