Margarella violacea
Encyclopedia
Margarella violacea is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

, a marine gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Trochidae
Trochidae
The Trochidae, common name top snails, are a taxonomic family of very small to large sea snails, marine gastropod molluscs in the clade Vetigastropoda ....

, the top snails.

Description

The size of an adult shell varies between 7 mm and 13.5 mm. The purplish-pink shell is imperforate, orbicular-conical, thin and smooth. There are four swollen whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...

.The suture is scarcely impressed. The rounded-quadrangular aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

 is angular above, and subangular at the base of slightly thickened and arcuate columella. The umbilico-columellar tract is excavated.

Distribution

This species occurs in the Atlantic Ocean on the coast of Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 and the Falkland Islands
Falkland Islands
The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...

, i.e. in the Magellanic Region.

External links

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