Odostomia mauritiana
Encyclopedia
Odostomia mauritiana is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
of the protoconch
are moderately large, helicoid, elevated, about one-fifth immersed in the first of the succeeding whorls
and having their axis at a right angle to them. The five whorls of the teleoconch are flattened, angulated at the periphery and weakly shouldered at the
summit; the latter falls somewhat anterior to the periphery of the preceding whorl and lends to it a somewhat constricted appearance at the well-impressed suture. The whorls are marked by extremely fine, closely placed, wavy spiral striations, which are visible only under
very high magnification. The periphery of the last whorl is somewhat angulated. The base of the shell is very broad, gently rounded, somewhat pinched at the narrow umbilicus. The aperture
is elongate-ovate, somewhat prolonged at the junction of the outer lip
and columella. The posterior angle is acute. The outer lip is thin, somewhat effuse. The slender columella is decidedly curved, slightly revolute, provided with a prominent oblique fold at its insertion.The parietal wall is covered by a strong callus which lends the periostracum an
almost continuous appearance.
.
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 small shell measures 2.1 mm. It is umbilicated, elongate-ovate conic, semitransparent, polished. The 2½ whorlsWhorl (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...
of the protoconch
Protoconch
A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
are moderately large, helicoid, elevated, about one-fifth immersed in the first of the succeeding whorls
and having their axis at a right angle to them. The five whorls of the teleoconch are flattened, angulated at the periphery and weakly shouldered at the
summit; the latter falls somewhat anterior to the periphery of the preceding whorl and lends to it a somewhat constricted appearance at the well-impressed suture. The whorls are marked by extremely fine, closely placed, wavy spiral striations, which are visible only under
very high magnification. The periphery of the last whorl is somewhat angulated. The base of the shell is very broad, gently rounded, somewhat pinched at the narrow umbilicus. 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 elongate-ovate, somewhat prolonged at the junction of 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....
and columella. The posterior angle is acute. The outer lip is thin, somewhat effuse. The slender columella is decidedly curved, slightly revolute, provided with a prominent oblique fold at its insertion.The parietal wall is covered by a strong callus which lends the periostracum an
almost continuous appearance.
Distribution
The type specimen of this marine species was found in the Indian Ocean off MauritiusMauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
.