''Seguenzia costulifera'' 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), ...

of extremely small deep water

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 ...

Seguenziidae Seguenziidae is a family (biology), family of very small deepwater sea snails, marine (ocean), marine gastropod mollusks in the superfamily Seguenzioidea (according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), taxonomy of the Gastr ...

.WoRMS (2013). ''Seguenzia costulifera''. Retrieved through:

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

at http://www.marinespecies.org/aphia.php?p=taxdetails&id=492447 on 2013-06-10

Description

(Original description by M. Schepman) The height of the yellowish white shell attains 5 mm. The rather small shell has a conoidal shape, with a high

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 ...

and convex base. It is scalar and rimate. It contains about 7

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 of which the upper one forms the smooth, bulbous nucleus, followed by 2 whorls, which have a strong median keel and traces of a third one below the suture. These lirations become more conspicuous on the lower whorls, which have the median keel, another one just below the suture and in some parts traces of a third one, running entirely or partly in the deep suture. Moreover, the whole shell is covered with microscopic, close-set, spiral threads. This

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 ...

is crossed by conspicuous riblets, fainter on the upper whorls, very strong on the lower ones, and by very fine growth-striae. The riblets are not close-set and form conspicuous spines below the suture of the lower whorls. When they cross the upper spiral, they run obliquely from behind and are curved in the lower part of the space between the upper and median keel, being concave below. Below this median keel they are convex. On the

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 ...

runs a third keel, which is crenulated by the ribs. This is also the case with the median keel, though not so strong;.aA some distance from the third keel a fourth one makes its appearance, this is a little fainter and less crenulate, the riblets between it and the third keel being also weaker. The interspaces of the keels described above are conspicuously concave. From the fourth keel until the centre run 5 spirals, of which the distal one at a considerable distance from the 4th keel. The innermost borders the umbilicus. These spirals are narrow, cord-like, with large interspaces, crossed by riblets in very various direction. The umbilicus is rather large, but nearly closed by the

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 ...

r margin, leaving only a fissure. 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 incomplete, a rather broad but not deep fissure at the upper part, rounded and turned up behind. The shape of the aperture is subquadrangular, irregular by the terminations of the keels. The columellar margin is expanded towards the left, formed by a deep, rounded sinus above and another narrower one below, with a strong tooth between them. This tooth is strongly compressed, as if formed by pinching the columellar margin.Schepman 1908-1913, The Prosobranchia of the Siboga Expedition; Leyden,E. J. Brill,1908-13
/ref>

Distribution

This marine species occurs off

Sulawesi Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...

, Indonesia.

References

External links

Biodiversity Heritage Library (1 publication)

Encyclopedia of Life

World Register of Marine Species
{{Taxonbar, from=Q14326677 costulifera Gastropods described in 1909