''Xanthodaphne araneosa'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Raphitomidae Raphitomidae is a Family (biology), family of small to medium-sized sea snails, marine (ocean), marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families" ...

.MolluscaBase (2019). MolluscaBase. Xanthodaphne araneosa (R. B. Watson, 1881). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=709383 on 2019-08-17

Description

''X. araneosa'' are very small sea snails, with shell lengths reaching up to 5.6 mm. The shell is yellowish, without gloss, minutely ribbed, and faintly spiraled. The spiral has a small, broad, scalar, sharp-pointed

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. Spire ...

with a slightly swollen

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, 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 ...

and rounded base, produced into a square, prominent, and one-sided snout. 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 " ...

is buff in color.

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 ...

longitudinal structure is exceedingly fine, showing faint, microscopic scratches in the line of growth. At distances of about 1/100 of an inch apart, these raise into small, sharpish, round-topped riblets, which run continuously from the suture to the snout, though on the base and below it they become smaller. On primitive

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). In nature File:Photograph and axial plane floral diagra ...

s, these are of course less marked and more close set. In the intervals of the larger riblets, one or two fainter ones occasionally appear. Below the slightly concave sinus area is an obtuse angulation, accentuated by the slight prominence of the two small spiral threads which lie there. Below this, on the

above the

lip The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Mammal lips are soft, movable and serve to facilitate the ingestion of food (e.g. sucklin ...

corner, there are about 5 other small spirals that are not so prominent. On the lower part of the body and on the base, they are weaker but become stronger again towards the point of the base and on the snout. The intersection of these with the spirals produces a slight spider-web-like appearance (on the property the name of the

epithet An epithet (, ), also a byname, is a descriptive term (word or phrase) commonly accompanying or occurring in place of the name of a real or fictitious person, place, or thing. It is usually literally descriptive, as in Alfred the Great, Suleima ...

is based). The spire is rather short and broad, scalar, and conical. The protoconch consists of 4½ very small, conical, scalar, convex, buff whorls, parted by a deep suture. The first whorl and half are closely spirally striated with about 10-minute threads. These threads, which are at first almost simple, are by degrees more and more fretted by longitudinals, which break up the threads into minute tubercles. Toward the end of the second whorl longitudinal and oblique bars appear somewhat vaguely and confusedly. But presently, the distinct arrangement appears of short little bars above and a network on the lower part of the whorls. The shell contains 7½ whorls in all, but the shell is very likely hardly full-grown. They are almost horizontal above, with a flat or faintly concave sinus-area, slightly angulated at the shoulder, and below this cylindrical or a very little convex to the lower suture. The last is rather short, a little tumid, with a long pillar-line on the left side, and a small square prominent snout on the right. The suture is very slight in consequence of the up lap of the whorls at their junction, but of course, strongly marked by the angulation of the line of junction. The

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is oblong, triangularly pointed above, and ending in a very square broadish

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 i ...

below. The outer

is flatly arched, with a slight angulation below the sinus-area and a marked pinch-in where it turns to form the siphonal canal. Its edge-line is very straight and scarcely prominent, but has a high shoulder above, between which and the body lies the deepish, rounded, and open-mouthed sinus. The inner lip is very thin and narrow, and dying out very early on the scarcely oblique, twisted, sharp

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

-edge. Its line across the body is very short and convex but is very concave at its junction with the long, scarcely oblique columella.

Distribution

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of this was found off St. Thomas, Caribbean Sea; also, off

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

and the

Virgin Islands The Virgin Islands () are an archipelago between the Atlantic Ocean, North Atlantic Ocean and northeastern Caribbean Sea, geographically forming part of the Leeward Islands of the Lesser Antilles in the Caribbean, Caribbean islands or West Indie ...

References

External links

* {{DEFAULTSORT:Xanthodaphne Araneosa araneosa Gastropods described in 1881