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''Bela dyscrita'' 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 attains 8.9 mm (Original description) The thin, white shell is narrowly oblong or fusiform, with a longish, scarcely tumid
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 ...
, a shortish, conical, convexly whorled, small-pointed, shallow-sutured
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 ...
, and a long conical base. There are delicate thread-like curved, longitudinal lines of growth, which are strongest near the top of the whorls. The whole surface is equably covered with fine, faintly raised, rounded, spiral threads. They are slightly fretted by the longitudinals. Between them are little rounded furrows of about twice their breadth. The spiral threads are porcellanous, the furrows translucent white, and the surface is a little glossy. The spire is rather short, conical, but slightly concave, with hardly any interruption in its profile-lines by the very slightly impressed suture and the convexity of the whorls. 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 ...
consists of 2 rounded subcylindrical
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 rising to a small rounded point, where the extreme tip hardly projects and is bent down on one side. It is smooth and glossy, but retains traces of a ruddy epidermis with minute spiral threads. The shell contains 6 whorls in all. These are of regular but rapid increase, rather high and broad, convex, but sloping, and not tumid. The body whorl is very long and full, though not tumid. And there is little contraction on the long conical base. The suture is slightly impressed and rather oblique. 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 large, open, and oblong, pointed above, scarcely contracted below, but truncated at the end of the broad open
siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...
. 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 very equably curved in both its planes. It has a somewhat high and prominent shoulder above, between which and the body whorl lies the rather deep, wide, rounded sinus. The inner lip shows is a thin glaze on the body and on the long
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 ...
, which is cut off in front with a long, thin, twisted, oblique edge.Watson, R.B. (1886) Report on the Scaphopoda and Gasteropoda collected by the H. M. S. Challenger during the years 1873–76. Report on the Scientific Results of the Voyage of the ‘Challenger’ (Zoology), 15, 1–756, 50 pls
/ref>


Distribution

This marine species occurs in the Caribbean Sea off
Anguilla Anguilla ( ) is a British Overseas Territory in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Saint Martin. The territo ...
, St Thomas and the
Virgin Islands The Virgin Islands ( es, Islas Vírgenes) are an archipelago in the Caribbean Sea. They are geologically and biogeographically the easternmost part of the Greater Antilles, the northern islands belonging to the Puerto Rico Trench and St. Croix ...


References


External links

* {{Taxonbar, from=Q30595199 dyscrita Gastropods described in 1881