''Mangelia eucosmia'' 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)
This is a

taxon inquirendum In biological classification, a ''species inquirenda'' is a species of doubtful identity requiring further investigation. The use of the term in English-language biological literature dates back to at least the early nineteenth century. The term t ...

Description

The length of the shell attains 12.4 mm, its diameter 4 mm. (Original description) The slender shell has an elongate-conic shape. It is white with narrow brown bands. The type specimen contains 9

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 forming an elevated

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 ...

. 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 ...

consists of 2½ whorls, dextral, strongly rounded and smooth, The subsequent whorls show a strong shoulder one-third of the distance between the sutures anterior to the summit, the rest well rounded. They are marked by strong, narrow, sinuous, slightly protractive, axial ribs, of which 10 occur upon the first, 12 upon the second and third, 14 upon the fourth and fifth, and 16 upon the penultimate whorl. The intercostal spaces are about three times as wide as the ribs. The spiral

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

consists of moderately broad, low, flattened spiral lirations, separated by channels a little less in width than the lirations. These lirations grow gradually wider from the summit to the periphery. There are 14 of them between the sutures on the penultimate whorl. The base of the shell is attenuated, marked by the continuations of the axial ribs and about 14 spiral lirations. Those of the outer half where the ribs are absent are much stronger than the rest. 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 almost oval, decidedly expanded at the posterior angle, where the outer lip is somewhat reflected by the shallow channel. The middle of the outer lip is slightly inbent and thin. The columella is sinuous and somewhat twisted. It is covered by a thin callus which extends up on the parietal wall.

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=Q39091012 ÷ eucosmia Gastropods described in 1915