''Mitromorpha biplicata'' 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 ...

Mitromorphidae Mitromorphidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Mitromorphidae Casey, 1904. In: MolluscaBase (2018). Accessed through: World Register of Marin ...

Description

The length of the shell varies between 4 mm and 8 mm. (Original description) The small shell is biconic and cancellated. It is yellowish or whitish or with brown flammules. The protoconch is glassy, white, globose and consists of 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. The five or six other whorls are hardly rounded. The sculpture consists of about (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 ...

) sixteen spiral squarish riblets with about equal interspaces, in which near 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 ...

of the adult a fine intercalary thread appears. The spiral sculpture is crossed by incremental lines and numerous faint rounded transverse ribs which go nearly across the whorl, but which are chiefly evident through the rounded waves they form on the spiral riblets, especially behind the periphery of the whorls. The suture is hardly distinguishable. The

is narrow. The outer lip lis irate within, a little patulous. The inner lip is plain, with two strong plications near its middle, the posterior the largest. None of the specimens had completed the thickening of the outer lip and the glazing of the columella which mark the adult state, but several were very near it. The surface of the shell is glossy except for the incremental lines.Dall W. H. 1889. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877–78) and in the Caribbean Sea (1879–80), by the U.S. Coast Survey Steamer "Blake", Lieut.-Commander C.D. Sigsbee, U.S.N., and Commander J.R. Bartlett, U.S.N., commanding. XXIX. Report on the Mollusca. Part 2, Gastropoda and Scaphopoda. Bulletin of the Museum of Comparative Zoölogy at Harvard College 18: 1–492, pls. 10–40

Distribution

This species occurs in the Atlantic Ocean from Georgia to

Barbados Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate). ...

and

Guadeloupe Guadeloupe (; ; gcf, label=Antillean Creole, Gwadloup, ) is an archipelago and overseas department and region of France in the Caribbean. It consists of six inhabited islands—Basse-Terre, Grande-Terre, Marie-Galante, La Désirade, and the ...

at depths between 10 m and 805 m; it is also recorded from

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

References

W.H. Dall (1889) ''A preliminary catalogue of the shell-bearing marine mollusks and brachiopods of the southeastern coast of the United States, with illustrations of many of the species''; Bulletin of the United States National Museum ; no. 37

External links

Rosenberg G., Moretzsohn F. & García E. F. (2009). ''Gastropoda (Mollusca) of the Gulf of Mexico'', Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas
* * {{DEFAULTSORT:Mitromorpha Biplicata biplicata Gastropods described in 1889