''Cirsonella ateles'' 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 ...
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 ...
Skeneidae
The Skeneidae are a speciose family of minute to small marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P.; Gofas, S. (2013). Skeneidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php ...
.
Description
The white shell attains a height of 2 mm, its diameter also 2 mm. It is a rather solid, shining shell with a narrow and deep
umbilicus. The
apex is obtuse. The
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 ...
is composed of four convex
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, separated by a marked
suture. 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 ...
goes slightly down to 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 ...
. The surface is smooth, except for the base of the body whorl, which has, seen from the periphery, low concentric striae, that disappear at a considerable distance from the umbilicus. The circular aperture has a continuous
peristome. The
columella has a thick, narrow callus that hardly reflects on the umbilical opening in young specimens but cover it completely in adults. The lip is simple.
Dautzenberg P. & Fischer H. (1896). Dragages effectués par l'Hirondelle et par la Princesse Alice 1888–1895. 1. Mollusques Gastropodes.; Mémoires de la Société Zoologique de France 9: 395–498, pl. 15-22
(described as ''Tharsis (?) ateles'')
Distribution
This species occurs in the Atlantic Ocean off the Azores
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, anthem= ( en, "Anthem of the Azores")
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, map_caption=Location of the Azores wi ...
.
References
* Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213
{{DEFAULTSORT:Cirsonella Ateles
ateles
Gastropods described in 1896