''Anatoma alta'' is a species of minute

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 or

micromollusk A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also ...

in the family

Anatomidae Anatomidae is a family of minute sea snails, marine gastropod mollusks in the clade Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). Anatomidae was raised to the rank of subfamily to the rank of family ...

Description

The shell grows to a length of 2.5 mm. The thin, white shell has a globose shape. It is transparent and strongly sculptured. It has a tumid base, a small umbilical chink. It has a short subscalar spire (on which the old canal slit forms the edge of the successive whorls), and a smallish somewhat prominent rounded tip. Its sculpture shows frequent, strongish, rounded, longitudinals. The curved riblets radiate out from the sutures. They are of much the same strength on the base as above. The spirals are located at about one-third of its height from the suture. 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 ...

is somewhat feebly carinated by the old canal scar, which is depressed and finely scored across between the narrow slightly projecting edges of the lip. On the upper surface a few very obsolete spirals may be seen. The whole base is reticulated by spiral threads, which are closer set, but almost as strong as the radiating riblets. The conical spire is rather depressed and rises regularly to the extreme tip. The apex is round and prominent. The five

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 are flat and sloping above. They are carinated below the carina towards the mouth slightly openly constricted and then tumid on the base. The suture is impressed. The aperture is round. The outer lip is freely curved. The thin inner lip is concave at the base of the columella, straight, rounded, and very much expanded on the columella with an angulated and very patulous junction to the outer lip in front. There is a small umbilical furrow and chink half hidden behind it. (original description by Watson)G.W. Tryon (1890), Manual of Conchology vol. XII
/ref>

Distribution

This species occurs in the Caribbean Sea, the Gulf of Mexico and in the Atlantic Ocean off Brazil, the Azores and Tristan da Cunha at depths between 20 mm and 820 m.

References

* Rosenberg, G., F. Moretzsohn, and E. F. García. 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.

External links

{{Taxonbar, from=Q4752241 Anatomidae Gastropods described in 1886