''Daphnella arafurensis'' 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), ...

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 ...

Raphitomidae Raphitomidae is a Family (biology), family of small to medium-sized sea snails, marine (ocean), marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families" ...

Description

The length of the shell attains 15 mm, its diameter 4⅓ mm. (Original description) The fusiform shell is whitish, faintly banded with light brown. It is spirally ridged and striated and marked with the flexuous lines of growth. This species is peculiar on account of the absence of longitudinal ribs. The shell contains 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. The two whorls in the

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called " ...

are globose, microscopically reticulated, but appearing smooth under an ordinary lens, rather large. The subsequent five are convex, a little constricted beneath the suture, and spirally ridged and striated. The upper whorls have four or five principal lirae, the uppermost falling just beneath the slight constriction, and the others below at equal distances. The whorls are thickened at or immediately under the sutural line with an elevated ridge, and between this and the first lira and in the interstices between the other lirae the surface is finely striated. 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 ...

is elongate, has about thirty-one ridges in addition to the minute interstriation. 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 narrow, contracted anteriorly into a short, broadish

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 i ...

, together equalling almost half the total length of the shell. 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 ...

is perpendicular, curving a little to the left in front, and coated with a very thin callosity. 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 ...

is thickened exteriorly, arcuate in the middle, faintly sinuated towards the lower extremity, and rather deeply notched in the slight constriction of the whorl near but not at the suture.
Smith, E.A. 1884. ''Mollusca''. pp. 34–116, 487–508, 657–659, pls 4–7. In, Report on the Zoological Collections made in the Indo-Pacific Ocean during the voyage of the H.M.S. 'Alert ' 1881-2. London : British Museum Trustees, printed by Taylor & Francis

Distribution

This marine species occurs in the

Arafura Sea The Arafura Sea (or Arafuru Sea) lies west of the Pacific Ocean, overlying the continental shelf between Australia and Western New Guinea (also called Papua), which is the Indonesian part of the Island of New Guinea. Geography The Arafura Sea is ...

Torres Straits The Torres Strait (), also known as Zenadh Kes ( ">�zen̪ad̪ kes/nowiki>), is a strait between Australia and the Melanesian island of New Guinea. It is wide at its narrowest extent. To the south is Cape York Peninsula, the northernmost e ...

, Albany Passage; Queensland, Australia.

References

* Hedley, C. 1922. ''A revision of the Australian Turridae.'' Records of the Australian Museum 13(6): 213–359, pls 42–56

External links

* {{DEFAULTSORT:Daphnella Arafurensis arafurensis Gastropods described in 1884 Gastropods of Australia