''Danilia affinis'', is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

Chilodontidae.

Description

The height of the shell attains 10 mm. The rather thin, imperforated shell has a conical

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 rounded, inflated

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

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 ...

shows elevated spiral cords, slightly unequal in size and narrower than interspaces, crossed by minute and numerous prosocline lamellae which override the cords. The

peristome Peristome (from the Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mosses In mosses, ...

is flaring in adult shells, with a distinct outer varix and with internal denticles elongated in the spiral direction. 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 ...

has a strong denticle. The colour of the shell is whitish with the inner nacre showing through, with vague brownish flames on specimens from shallower sites. The inside of the round

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 nacreous. This species is distinguished from ''

Danilia tinei ''Danilia tinei'' is a species of sea snail, a marine gastropod mollusk in the family (biology), family Chilodontidae (gastropods), Chilodontidae. Taxonomy Tommaso di Maria Allery Monterosato, Monterosato (1914) figured the holotype from Calca ...

'' in having the axial lamellae minute and about three times more numerous, the whitish colour and the more inflated and more fragile shell, with more convex whorls.

Distribution

This species occurs in the Atlantic Ocean off the

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

and on Atlantic seamounts at depths between 300 m and 730 m.

References

* Vilvens C. & Héros V. 2005. ''New species and new records of Danilia (Gastropoda: Chilodontidae) from the Western Pacific''. Novapex 6(3) : 53–64 {{DEFAULTSORT:Danilia Affinis affinis Gastropods described in 1896