''Agathotoma merlini'' 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 ...

. First described in 1910, its species name refers to

Martial Henri Merlin Martial Henri Merlin (20 January 1860 – 8 May 1935; also Martial Merlin) was a French colonial administrator of the 19th and 20th centuries. He served as the governor-general of Guadeloupe (1901–1903), French West Africa (1907–1908 and 1919 ...

, governor-general of

French Congo The French Congo (french: Congo français) or Middle Congo (french: Moyen-Congo) was a French colony which at one time comprised the present-day area of the Republic of the Congo and parts of Gabon, and the Central African Republic. In 1910, i ...

Description

The size of the shell varies between 5 mm and 8.5 mm; its diameter 3 mm. The solid shell is very elongated with a fusiform-subcylindrical 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 ...

consists of 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 floral ...

s. The initial whorls are smooth and convex, while the remaining whorls are slightly convex. The suture is appressed. The shell's

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 ...

includes longitudinal ribs, which are narrower than their intervals, numbering 10 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 ...

, with extremely fine striae visible only under magnification. 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 narrow, constituting less than half the shell's total length. The columella is slightly excavated at the top and subtly twisted at the base. The outer lip is smooth on the inner side, featuring a sinus at the top and is inflected below the sinus. The shell is primarily white with deciduous yellowish areas. The last three whorls exhibit a brown subsutural zone, interrupted by the lower extremities of the ribs, which remain white. The columella is tinged with dark brown. Dautzenberg P. (1910). Contribution à la faune malacologique de l'Afrique occidentale. Actes de la Société Linnénne de Bordeaux 44: 1-174 pl. 1-4, pp. 73-75

Distribution

It occurs on the westcoast of Africa (

Mauritania Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber: ''Agawej'' or ''Cengit''; Pulaar: ''Moritani''; Wolof: ''Gànnaar''; Soninke:), officially the Islamic Republic of Mauritania ( ar, الجمهورية الإسلامية ...

and

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 � ...

), and also on the islands of São Tomé and

Príncipe Príncipe is the smaller, northern major island of the country of São Tomé and Príncipe lying off the west coast of Africa in the Gulf of Guinea. It has an area of (including offshore islets) and a population of 7,324 at the 2012 Census;

References

External links

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1-1295.
*
MNHN, Paris: syntype
{{Taxonbar, from=Q4691573 merlini Invertebrates of São Tomé and Príncipe Gastropods described in 1910 Invertebrates of Africa