''Propebela subvitrea'' 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 13.5 mm. (Original description) The shell is translucent, white, thin but firm. It has a fusiform shape. It is moderately stout, with a high, regularly tapered, acute

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 ...

, consisting of about six rounded

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. These are crossed by rather thin, prominent ribs, strongly bent in a sigmoid curve, and having on the lower whorls a rather faint spiral

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 ...

. The shell shows four to five whorls below 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 ...

. These are strongly convex and a little swollen at the rounded shoulder, which is rarely somewhat angulated, and without a definite subsutural band. The suture is strongly impressed, the upper part of the whorl rising rather abruptly from it. The protoconch consists of about two small, prominent whorls. The first is small, rounded, slightly mamilliform, and a little prominent. The next, constituting the greater part of the protoconch, increases rapidly and is decidedly prominent and somewhat obliquely placed, and bears about four or five raised, revolving lines, which are sometimes crossed by distinct lines of growth. The suture between the last protoconch whorl and the next is strongly marked and more oblique than any of the others. The remaining whorls are crossed by rather conspicuous, sharp, and rather elevated ribs. These are strongly excurved at and just above the shoulder, curving forward rapidly to the suture, and bending forward more gradually below the shoulder, forming a distinct sigmoid curve. The interspaces between the ribs are much wider than the ribs themselves, distinctly concave, and crossed by rather feeble cinguli, which arc usually not apparent ou the ribs themselves. On the upper whorls the spiral lines are usually more conspicuous than on the lower ones, but are often indicated chiefly by rather close, shallow furrows. 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 ...

the ribs extend to the base of the

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 ...

before they fade out, and the spiral

becomes coarser and a little more evident on its anterior part and on the canal. The surface is also a little roughened by faint lines of growth, parallel with the ribs. 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 oblong-ovate, rather narrow. The outer lip is sharp, thin, projecting forward in the middle in a broadly rounded curve, and slightly receding just above the shoulder, so as to form a broad and shallow sinus a little removed from the suture. The siphonal canal is nearly straight, a little prolonged, distinctly constricted at its base by the incurvature of the outer lip. The columella is straight, tapering anteriorly, its inner edge forming a well-marked sigmoid curve. The

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 ...

is indistinct. The color of the shell is translucent bluish white. The surface is not glossy, but the texture is more vitreous and delicate than in the more northern and shallow-water species of ''Propebela''.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: 139–294, pls. 28–32.

Distribution

This marine species occurs off

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

, USA.

References

External links

* {{DEFAULTSORT:Propebela Subvitrea subvitrea Gastropods described in 1884