''Thesbia dyscrita'' 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 in the family

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". '' Malacologia'' 47(1-2). . 3 ...

.MolluscaBase eds. (2020). MolluscaBase. Thesbia dyscrita (R. B. Watson, 1881). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=533491 on 2020-04-08

Description

The maximum length is 9 mm. (Original description) The thin, white shell is narrowly oblong or fusiform, with a longish, scarcely tumid

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 ...

, a shortish, conical, convexly whorled, small-pointed, shallow-sutured, conical spire, and a long conical base. Sculpture. Longitudinals : there are delicate threadlike curved lines of growth, which are strongest near the top of 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 flo ...

s. Spirals: the whole surface is equably covered with fine, faintly raised, rounded threads. They are slightly fretted by the longitudinals . Between them are little rounded furrows of about twice their breadth. Colour: the spiral threads are porcellaneous, the furrows translucent white, and the surface is a little glossy. The spire is rather short, conical, but slightly concave, with hardly any interruption in its profile-lines by the very slightly impressed suture and convexity of the whorls. 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 rounded subcylindrical whorls rising to a small rounded point, where the extreme tip hardly projects and is bent down on one side. It is smooth and glossy, but retains traces of a ruddy epidermis with minute spiral threads. The shell contains 6 whorls in all, of regular but rapid increase, rather high and broad, convex, but sloping, and not tumid. The last is very long and full, though not tumid. And there is little contraction on the long conical base. The suture is slightly impressed, rather oblique. The aperture is large, open, and oblong, pointed above, scarcely contracted below, but truncated at the end of the broad open

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

. The outer lip is very equably curved in both its planes. It has a somewhat high and prominent shoulder above, between which and the body whorl lies the rather deep, wide, rounded sinus. The inner lip shows a thin glaze on the body and out on the long columella, which is cut off in front with a long, thin, twisted, oblique edge.

Distribution

THis species was found in the Caribbean Sea off Sombrero Island, Anguila at a depth of 823 m.

References

External links

* {{DEFAULTSORT:Thesbia Dyscrita dyscrita Gastropods described in 1881