''Mangelia helga'' is a species of

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 ...

Mangeliidae Mangeliidae is a monophyletic family of small to medium-sized, predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. Bouchet, P. (2011). Mangeliidae P. Fischer, 1883. In: MolluscaBase (2016). Accessed through: World Regis ...

.P. Bartsch (1915), Report on the Turton collection of South African marine mollusks, with additional notes on other South African shells contained in the United States National Museum; Bulletin of the United States National Museum v. 91 (1915)

Description

The length of the shell attains 3 mm, its diameter 1 mm. (Original description) The shell has a wax yellow color. The 1½

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 of 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 well rounded and apparently smooth. The subsequent whorls are strongly, tabulatedly shouldered. They are marked by strong, spiral cords, of which 3 occur between the angle of the shoulder and the suture on all the whorls. These are a little wider than the spaces that separate them. On the middle of the tabulated shoulder, a slender spiral cord begins on the first whorl, which increases in strength until it is about half as strong as those anterior to it on the

body whorl The body whorl is part of the morphology of the 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. In gastropods In gastropods, the b ...

. The sutures are strongly constricted. The periphery of the body whorl is marked by a cord fully as strong as those posterior to it. The base of the shell is moderately prolonged, slightly rounded, marked by three spiral cords which are almost as strong as those on 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 ...

and of about equal spacing with them. 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 opt ...

is feebly channeled posteriorly, decidedly so anteriorly. The outer lip is rendered sinuous by the spiral cords. The inner lip and parietal wall are covered with a thin callus.

Distribution

This marine species occurs off

Port Alfred A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ha ...

, South Africa.

References

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1-1295.
{{Taxonbar, from=Q39091227 Endemic molluscs of South Africa helga Gastropods described in 1915