''Gymnobela engonia'' is a species of sea snail, a marine gastropod

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 group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". ''Malacologia'' 47(1-2). . 39 ...

Description

The length of the shell attains 17 mm, its diameter 3.5 mm. (Original description) The somewhat solid, white, more or less translucent shell has a stout-fusiform shape. 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 ...

is about equal in length to 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 a ...

, which is shouldered, decidedly turreted, and tapered regularly to an acute

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. The shell contains five whorls below the protoconch, strongly angularly shouldered at about the middle, the portion above the shoulder forming a wide, abruptly sloping subsutural band, which is usually slightly concave in the middle, but swells a little where it joins the suture. The whorls are flattened below the shoulder and a little narrowed at the suture, which is strongly impressed. 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 ...

on the subsutural band consists of numerous, close, revolving lines, most distinct towards the shoulder, and of small, slightly raised, thin riblets, which are most distinct close to the suture and strongly excurved in the middle of the band, but bend forward strongly to the angle of the shoulder, where most of them disappear or blend with the ribs and lines of growth a little farther forward. Below the shoulder the surface is covered by many, rather thin, closely arranged, revolving cinguli, which on the whorls of the spire are separated by interspaces about twice their own width, but become much closer on the middle of the body whorl, gradually becoming coarser and more widely separated as they approach the siphonal canal, those on the anterior part being also thicker and more obtuse. Numerous rather small and slightly elevated ribs commence at the shoulder and curve obliquely forward across the convex part of the whorls, extending to the suture on the upper whorls, but mostly fading out at the middle of the body whorl. These ribs are obtusely rounded and wave-like, the interspaces being shallow, concave, in breadth about equal to the ribs. On the body whorl there are from twenty-five to thirty. On the spire-whorls the intersections of the cinguli and ribs, which are of about the same size, produce a pretty regularly cancellated structure, but on the body whorl the cinguli are more numerous and less prominent than the ribs. The protoconch is chestnut-brown and consists of about 2½ regularly increasing whorls, the apical one being very small and regularly coiled ; this surface appears to have been minutely cancellated by microscopic lines. The

is irregularly oblong or oblong-ovate, strongly angulated by the shoulder, and decidedly widest at the base of the

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

. The siphonal canal is short, somewhat constricted and nearly straight. The outer

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

is thin, projecting forward below the shoulder, with a broad, rounded, rather shallow sinus at the middle of the subsutural band and a little removed from the suture. The operculum is not present in the alcoholic specimens. Verrill A. E. (1884). ''Second catalogue of mollusca recently added to the fauna of the New England Coast and the adjacent parts of the Atlantic, consisting mostly of deep sea species, with notes on others previously recorded.'' Transactions of the Connecticut Academy of Arts and Sciences, 6(1): 139-294, pl. 28-32

Distribution

This marine species occurs off

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the Can ...

, USA and was found off the

Nantucket Shoals Nantucket Shoals is an area of dangerously shallow water in the Atlantic Ocean that extends from Nantucket Island, Massachusetts, eastward for and southeastward for ; in places water depth can be as shallow as . Depth soundings are unpredictable d ...

at a depth of 2941 m.

References

* Sysoev A.V. (2014). Deep-sea fauna of European seas: An annotated species check-list of benthic invertebrates living deeper than 2000 m in the seas bordering Europe. Gastropoda. Invertebrate Zoology. Vol.11. No.1: 134–155 * Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca. in: Costello, M.J. et al. (eds), European Register of Marine Species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Patrimoines Naturels. 50: 180-213.

External links

*
Bouchet & Warren, Revision of the North-East Atlantic bathyal and abyssal Turridae (Mollusca, Gastropoda); The Journal of Molluscan Studies, supplement 8, December 1980
{{DEFAULTSORT:Gymnobela Engonia engonia Gastropods described in 1884