''Curtitoma incisula'' is a species of

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 ...

Mangeliidae Mangeliidae is a monophyletic family of small to medium-sized, predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. Bouchet, P. (2011). Mangeliidae P. Fischer, 1883. In: MolluscaBase (2016). Accessed through: World Regis ...

Description

The length of the shell varies between 5.5 mm and 10.5 mm. (Original description) The shell is small, sub-fusiform, too short ovate. It contains about five or six turreted, flattened

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, which are angularly shouldered just below the suture. The subsutural band arises abruptly from the suture, nearly at right angles, and its surface is flat or slightly concave, marked by strongly recurved lines of growth, but mostly without spiral lines. The shoulder is often nearly right-angled. The whorls are decidedly flattened in the middle. There are 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 ...

, about twenty rather broad, flattened or rounded ribs, which are nearly straight, a little prominent and usually slightly nodose at the shoulder, but they disappear a short distance below it. They are separated by well excavated, concave grooves, deepest close to the shoulder. The most characteristic feature of 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 ...

is that the surface is marked by rather fine, but regular and distinct, sharply incised, narrow, revolving grooves, which are rather distant, with flat intervals. Of these, there are usually about three to five on the penultimate whorl, and about twenty to twenty-eight on the body whorl, the greater number being below the middle, on the siphon, where they become coarser and closer, with narrower rounded intervals. One of the sulci, just below the shoulder, is usually more distinct, and cuts the ribs so as to give their upper ends a subnodulous appearance. Below this there is usually a rather wide zone, without grooves usually no revolving lines above the shoulder. The apex is usually eroded. When perfect it is acute. 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 ...

has a very small and slightly prominent smooth apex. Its first whorl is marked with fine spiral lines. The next whorl has, at first, about three stronger, spiral, raised cinguli, which soon begin to be crossed by thin transverse riblets. 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 ...

measures about half the length of the shell. It is narrow ovate, or elliptical, angulated above. The siphonal canal is short, nearly straight, and a little narrowed at the base by an incurvature of the lip. The outer lip has a decided angle at the shoulder, below which the edge is well-rounded, and projects strongly forward, in the middle. The sinus, above the shoulder, is rather deep, wide, and evenly rounded within. The columella is strongly excavated in the middle, obliquely receding at the end. The shell is commonly greenish white and covered by a thin, close, greenish

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 ...

; but some specimens are clear white, and rarely pinkish. Verrill, A. E. 1882. Catalogue of marine Mollusca added to the fauna of the New England region, during the past ten years. Transactions of the Connecticut Academy of Arts and Sciences 5: 451–587, pls. 42–44, 57–58
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Distribution

This species occurs in the Northwest Atlantic Ocean,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and the

Gulf of Maine The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America. It is bounded by Cape Cod at the eastern tip of Massachusetts in the southwest and by Cape Sable Island at the southern tip of Nova Scotia in the northeast ...

; found at depths between 20 m and 190 m.

References

* Verrill, A.E. (1882) ''Catalogue of marine Mollusca added to the fauna of the New England region during the past ten years''. Transactions of the Connecticut Academy of Arts and Sciences, 5 (2) : 451–587 * Brunel, P., L. Bosse, and G. Lamarche. 1998. ''Catalogue of the marine invertebrates of the estuary and Gulf of St. Lawrence''. Canadian Special Publication of Fisheries and Aquatic Sciences, 126. 405 p.

External links

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682: 1–1295.

Trott, Thomas J. "Cobscook Bay inventory: A historical checklist of marine invertebrates spanning 162 years." Northeastern Naturalist 11.sp2 (2004): 261–324

Gulbin, Vladimir V. "Review of the Shell-bearing Gastropods in the Russian Waters of the East Sea (Sea of Japan). III. Caenogastropoda: Neogastropoda." The Korean Journal of Malacology 25.1 (2009): 51–70
* {{DEFAULTSORT:Curtitoma Incisula incisula Gastropods described in 1882