''Africolaria rutila'', common name the smooth horse conch, 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 ...

Fasciolariidae Fasciolariidae is a family of small to large sea snails, marine gastropod mollusks in the superfamily Buccinoidea. Species in Fasciolariidae are commonly known as tulip snails and spindle snails. The family Fasciolariidae most likely appeared ...

, the spindle snails, the tulip snails and their allies.Bouchet, P. (2012). Africolaria rutila (Watson, 1882). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=607897 on 2012-08-28

Description

The shell grows to a length up to 175 mm, perhaps more. The shell is spindle-shaped, with 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. Spire ...

and

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 ...

roughly equal in length. The

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 are evenly rounded, and the surface is sculpted with fine spiral threads. The siphonal canal is of moderate length. The inner

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 ...

features a single spiral

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 pleat at the base of the siphonal canal, occasionally accompanied by a second pleat nearby. The parietal region shows an indistinct, in-running spiral ridge just below the insertion of the outer lip. The interior of the outer lip is smooth, and the tip of the spire is slightly bulbous when intact, though it may appear worn or damaged. The shell is whitish, covered by a thin, pale horn-colored or orange-brown

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods an ...

, which is often eroded on the spire. The animal is yellowish-white to pale yellow in color.

Distribution

This marine species is endemic top South Africa and occurs off the west coast to the Namibian border and the

Agulhas Bank The Agulhas Bank (, from Portuguese for Cape Agulhas, ''Cabo das Agulhas'', "Cape of Needles") is a broad, shallow part of the southern African continental shelf which extends up to south of Cape Agulhas before falling steeply to the abyssal pla ...

at depths between 65 m and 500 m.

References

* Marais J.P. & R.N. Kilburn (2010) ''Fasciolariidae''. pp. 106–137, in: Marais A.P. & Seccombe A.D. (eds), Identification guide to the seashells of South Africa. Volume 1. Groenkloof: Centre for Molluscan Studies. 376 pp. * Snyder M.A., Vermeij G.J. & Lyons W.G. (2012) ''The genera and biogeography of Fasciolariinae (Gastropoda, Neogastropoda, Fasciolariidae).'' Basteria 76(1–3): 31–70. {{Taxonbar, from=Q4690087 Fasciolariidae Gastropods described in 1882