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

, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 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...

 Pyramidellidae
Pyramidellidae
Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea snails, marine heterobranch gastropod molluscs or micromolluscs....

, the pyrams and their allies.

Description

The white shell has an elongate-ovate shape. Its length is 3.6 mm. The nuclear 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...

 are deeply obliquely immersed in the first of the succeeding turns, above which only the tilted edge of the last volution projects. The five post-nuclear whorls are feebly rounded in the middle, strongly so at the slopingly shouldered summit, and moderately contracted at the suture. The periphery is weakly angulated. The base of the shell is rather long, moderately rounded and sloping gently from the periphery to the umbilical area. The sutures are well impressed. The entire surface of the spire and base are marked by fine retractive lines of growth and numerous very fine closely spaced wavy spiral striations. The 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 broadly oval. The posterior angle is obtuse. The outer lip
Lip (gastropod)
In the shell of a gastropod mollusk , the margin of the aperture is called the lip or the peristome. In other words, this is a term used to describe part of gastropod shell anatomy....

 is thin. The columella is slender, very strongly curved and very oblique. It is provided with a deep seated fold at its insertion. The parietal wall is covered with a thin callus.

External links

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