Odostomia clementina
Encyclopedia
Odostomia clementina is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
are obliquely immersed in the first post-nuclear turn, above which only the tilted edge of the last volution projects, which is marked by five slender spiral threads. The five post-nuclear whorls are well rounded, moderately contracted at the sutures, strongly slopingly shouldered at the summit. They are marked by strong, somewhat retractive axial ribs, of which 14 occur upon the first and second, 18 upon the third and the penultimate turn. In addition to the axial ribs, the whorls are marked by four spiral cords between the sutures, of which the second one anterior to the summit marks the angle of the shoulder. On the last two whorls the first basal is apparent in the strongly contracted sutures. The periphery of the body whorl
is marked by a spiral groove. The base of the shell is well rounded, somewhat attenuated anteriorly, and marked by five distant spiral cords which grow successively weaker from the periphery to the umbilical region. The broad spaces that separate these cords are marked by numerous fine, raised, axial threads. The aperture
is broadly oval. The posterior angle is obtuse. The outer lip
is thin, showing the external sculpture within, rendered sinuous by the spiral cords.The columella is moderately strong, slightly reflected, reenforced by the base, and provided with a slender fold at its insertion.
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 elongate-conic shell is vitreous. It measures 2.3 mm. The nuclear 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...
are obliquely immersed in the first post-nuclear turn, above which only the tilted edge of the last volution projects, which is marked by five slender spiral threads. The five post-nuclear whorls are well rounded, moderately contracted at the sutures, strongly slopingly shouldered at the summit. They are marked by strong, somewhat retractive axial ribs, of which 14 occur upon the first and second, 18 upon the third and the penultimate turn. In addition to the axial ribs, the whorls are marked by four spiral cords between the sutures, of which the second one anterior to the summit marks the angle of the shoulder. On the last two whorls the first basal is apparent in the strongly contracted sutures. The periphery of the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
is marked by a spiral groove. The base of the shell is well rounded, somewhat attenuated anteriorly, and marked by five distant spiral cords which grow successively weaker from the periphery to the umbilical region. The broad spaces that separate these cords are marked by numerous fine, raised, axial threads. 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, showing the external sculpture within, rendered sinuous by the spiral cords.The columella is moderately strong, slightly reflected, reenforced by the base, and provided with a slender fold at its insertion.