''Retidrillia pruina'' is a species of

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 ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

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 ...

Borsoniidae Borsoniidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Borsoniidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/ ...

.Bouchet, P. (2015). Retidrillia pruina (Watson, 1881). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=832443 on 2015-02-05

Description

The shell grows to a length of 21 mm. (Original description) The strong shell is white and dark-brown tipped. It has a biconical shape, with a short stout scalar

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 ...

, angulated

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, a roundly contracted marginated suture, and a small

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 ...

conically narrowed into a small unequal-sided snout.

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 sculpture—on the earlier whorls there are very small, narrow, oblique ribs originating in a mid-whorl row of tubercles, but on the body whorl the riblets almost disappear. There are fine scratches in the lines of growth. These are peculiarly sharp and regular in the sinus area. Spiral sculpture—the whorls are bisected by a strong angular keel, sparsely, but regularly, set with small round knobs, from which the longitudinal ribs descend.; Below the suture there is a narrow cylindrical collar of two fine contiguous threads. The sinus-area is free of these. But from the keel downwards the surface is covered by fine narrow rounded threads, separated by broader intervals. Near the keel these are crowded. On the point they are wider apart, on the base they are most sparse. Besides these, there is a delicate microscopic fretting. Colour: porcellaneous white, dead or frosted in the interstices, but pellucid and glossy on the spiral threads. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

is dark ruddy brown. The spire is conical, scalar, shortish, blunt. The apex consists of 3½ cylindrically globose rounded whorls separated by a linearly impressed suture. They rise to a flattened top, consisting of fully 1½ whorls, in the midst of which lies the very minute and immersed tip. These whorls are coloured of a deep, rich, translucent, faintly ruddy brown.;The earliest ones, perhaps from rubbing, are glossy, but further on they are crossed by crowded, curved, sharpish, almost microscopic riblets. Between which are finely microscopic spirals whose course is not quite uniform. Whorls 7½ but the shell is probably not quite full-grown. They are of very regular and slow increase, broad and short, each one laps up on the one before it, and is there shortly cylindrical, has then a pretty long, concave, and somewhat horizontal shoulder to the keel, which is right-angled. Below this the whorls are cylindrical with a slight contraction downwards to the inferior suture. The

contracts from the keel downwards, with a convexly conical and very unequally-sided base, produced into a small bluntly pointed snout. The suture is a very shallow rounded furrow defined by the infrasutural collar and the contraction of the whorls. 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 angularly pear-shaped, being truncate above and prolonged into the 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

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 ...

leaves the body at a right angle, and advances direct to the keel, from which point to the end of the snout it forms almost a straight line. Its edge is at the keel thrown out into a high shoulder, between which and the body lies the shallow, open, rounded sinus, with a narrow triangular shelf between it and the body whorl. The lip-edge is thin throughout. The inner lip is excavated somewhat deeply and flatly into the thickness of the shell, and runs on to the extreme point of the rather short and oblique

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 ...

, whose inner edge has a long gradual twist. R. Boog Watson, ''Mollusca of HMS 'Challenger'Expedition''; Journal of the Linnean Society of London, Zoology 15 (1881)
(described as ''Pleurotoma (Thesbia) pruina'' )

Distribution

This species occurs in the Northwest Atlantic Ocean found at depths between 878 m and 2359 m off the

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

and

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

, USA; in the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

References

* Pequegnat, W. E. 1983. ''The ecological communities of the continental slope and the adjacent regimes of the northern Gulf of Mexico.'' United States Department of the Interior, Minerals Management Service, Metairie, Louisiana. xv + 398 pp * McLean J. H. (2000). ''Four new genera for northeastern Pacific gastropods.'' The Nautilus. 114: 99–102.

External links

Bouchet P., Kantor Yu.I., Sysoev A. & Puillandre N. (2011) A new operational classification of the Conoidea. Journal of Molluscan Studies 77: 273–308.

Rosenberg G., Moretzsohn F. & García E. F. (2009). ''Gastropoda (Mollusca) of the Gulf of Mexico'', Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas

Serge GOFAS, Ángel A. LUQUE, Joan Daniel OLIVER, José TEMPLADO & Alberto SERRA (2021) - The Mollusca of Galicia Bank (NE Atlantic Ocean); European Journal of Taxonomy 785: 1–114
{{DEFAULTSORT:Retidrillia Pruina

pruina Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "bloom" ...

Gastropods described in 1881