''Clionella sinuata'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the ribbed turrid, is a

species In biology, a species is the basic unit of 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 the appropriate s ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

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 e ...

in the

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

Clavatulidae Clavatulidae is a taxonomic family of sea snails, marine gastropod mollusks in the superfamily Conoidea. The family is not well differentiated morphologically. Clavatulidae was raised, based on cladistic analysis, from subfamily to the family ...

. Fossils of this species have been reported from

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

localities on the west coast of South Africa.

Description

The size of an adult shell varies between 30 mm and 45 mm. The shell is variable in shape. 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 ...

varies from high to relatively low. 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). Whorls in nature File:Photograph and axial plane floral ...

s are not distinctly concave and have a narrow channel above. The subsutural cord is somewhat impressed. The axial ribs are going from strong (numbering 18-25 per whorl) to almost obsolete. The periphery contains a row of small nodules produced by the anal sinus, terminating short, low, flexuous plicate ribs. The spiral striae are not very distinct. The color of the shell is a pale rusty brown to brownish orange, under a blackish brown epidermis.G.W. Tryon (1884) Manual of Conchology, structural and systematic, with illustrations of the species, vol. VI; Philadelphia, Academy of Natural Sciences
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Distribution

This marine species occurs off the west coast of

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

References

* Kilburn, R.N. (1985). ''Turridae (Mollusca: Gastropoda) of southern Africa and Mozambique. Part 2. Subfamily Clavatulinae''. Ann. Natal Mus. 26(2), 417-470 * Branch, G.M. et al. (2002). ''Two Oceans''. 5th impression. David Philip, Cate Town & Johannesburg.

External links

* sinuata Gastropods described in 1778 {{clavatulidae-stub