''Seguenzia giovia'' 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 ...

.Rosenberg, G. (2013). ''Seguenzia giovia'' Dall, 1919. 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=492450 on 2013-06-10

Description

(Original description by W.H. Dall) The shell is higher (6 mm) than broad (5 mm). The shell resembles '' Seguenzia certoma'' Dall, 1919, but it is larger and differently sculptured. The minute nucleus is smooth, subglobular followed by seven

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 ...

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. The obscure suture is laid on the peripheral keel. The spiral sculpture shows four narrow prominent keels, of which the second is peripheral, the third marginates the base, and the fourth is on the base, the interspaces much wider and becoming narrower anteriorly. There are also seven closer even low threads on the base with subequal interspaces. The posterior wide interspaces are sculptured with close-set fine spiral thread. The axial sculpture shows numerous equal and equally spaced arcuate threads, with wide interspaces, which on the upper whorls bead the posterior carina, but later are chiefly visible in the interspaces and extend over the whole shell. The sulcus at 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 ...

next the body is shallow. 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 ...

beyond it is moderately produced and crenulate by the sculpture. The thin and arcuate

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 ...

has a very small notch at its base. There is a deep twisted perforate

umbilicus Umbilicus may refer to: *The navel or belly button *Umbilicus (mollusc), a feature of gastropod, Nautilus and Ammonite shell anatomy *Umbilicus (plant), ''Umbilicus'' (plant), a genus of over ninety species of perennial flowering plants *Umbilicus ...

and a thin layer of enamel on the body.Dall (1919) Descriptions of new species of Mollusca from the North Pacific Ocean; Proceedings of the U.S. National Museum, vol. 56 (1920)
/ref>

Distribution

The type specimen was found in the Pacific Ocean off Catalina Island, California.

References

External links

Biodiversity Heritage Library (2 publications)

Encyclopedia of Life

USNM Invertebrate Zoology Mollusca Collection

ITIS

World Register of Marine Species
{{Taxonbar, from=Q3734236 giovia Gastropods described in 1919