''Tropidoturris fossata'' 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 ...

Borsoniidae Borsoniidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Borsoniidae. Accessed through: World Register of Marine Species at http://www.marinespecies.or ...

.WoRMS (2015). Tropidoturris fossata. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=435086 on 2016-04-05 There is one subspecies: ''Tropidoturris fossata notialis'' Kilburn, 1986

Description

The size of the shell attains 20.4 mm. (Original description) The fusiform shell is acuminated at both ends. Its color is pale fulvous, obscurely spotted with brown, here and there tinged with light purple, and coloured anteriorly with a purplish band. 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 acute, gradately turreted. It contains 8

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. The first two are smooth, rounded, forming a papillary

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex, ...

. The third is angular and ribbed below the angle. The rest is deeply concave at the top, the concavity being bordered by a sharp erect keel, below which the whorls are slightly convex, with short very oblique plicae, and about 5 spiral lirae which are sharply angular at the top and slopingly compressed on the under side. The ''body whorl'' ais bout equal in length to the spire, slightly convex above, and tapering to the base. The oblique plicae against the keel become almost obsolete on the latter half of the whorl, while the spiral lirae numbering about 22 are quite as deep and broad as those on the upper whorls. 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 oblong, moderately wide, without any definite 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 ...

. 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 thin, with rather a broad sinus at the juncture of the whorl. The shell shows a distinct character, quite unlike any other known species. The sharp erect keel at the top of the whorls, the broad channel between this and the suture, and the numerous curiously sloping spiral lirae throughout, are its chief characteristics.G.B. Sowerby III (1904) Mollusca of South Africa; Marine investigations in South Africa , v. 2 (1904)

Distribution

This marine species occurs off Zululand, South Africa

References

* Kilburn R.N. (1986). ''Turridae (Mollusca: Gastropoda) of southern Africa and Mozambique. Part 3. Subfamily Borsoniinae''. Annals of the Natal Museum. 27: 633–720.
Tucker, J.K. 2004. ''Catalog of Recent and fossil turrids (Mollusca: Gastropoda).'' Zootaxa 682: 1–1295

External links

* {{DEFAULTSORT:Tropidoturris Fossata Endemic molluscs of South Africa fossata Gastropods described in 1903