''Stilla flexicostata'' is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

of sea snail, a marine gastropod

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 es ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". '' Malacologia'' 47(1-2). . 3 ...

Description

The length of the shell attains 2.25 mm, its diameter 1.25 mm. (Original description) The minute, white, semi-transparent shell has an oval-elongated shape. Its

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 longer than the body whorl. It contains five

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 flo ...

s, narrowly shouldered, with flexuous plicae, about 16 on the body whorl, microscopically spirally striate. The protoconch consists of 1½ smooth, minute whorls. The suture is deep. 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 ...

is oval and angled above. The outer

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

is somewhat thickened, sinuous, with a broad shallow sinus just below the suture. 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 ...

is arcuate, slightly callous. The anterior

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 ...

is short, rather oblique and truncated. The animal is unknown.Suter H. (1899). ''Revision of the New Zealand Pleurotomidae, with descriptions of six new species.'' Transactions and Proceedings of the New Zealand Institute. 31: 64-77, pl. 3
/ref>

Distribution

This marine species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

and occurs off Foveaux Strait, Stewart, Snares and Auckland Island

References

* Powell, A.W.B. 1979 ''New Zealand Mollusca: Marine, Land and Freshwater Shells'', Collins, Auckland * Spencer, H.G., Marshall, B.A. & Willan, R.C. (2009). ''Checklist of New Zealand living Mollusca.'' Pp 196-219. in: Gordon, D.P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch.

External links

*
Spencer H.G., Willan R.C., Marshall B.A. & Murray T.J. (2011). Checklist of the Recent Mollusca Recorded from the New Zealand Exclusive Economic Zone
{{DEFAULTSORT:Stilla Flexicostata flexicostata Gastropods described in 1899 Gastropods of New Zealand