Odostomia sitkaensis
Encyclopedia
Odostomia sitkaensis is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
of the protoconch
are almost completely immersed in the first of the succeeding volution. The whorls of the teleoconch are moderately rounded, rather high between the sutures, slightly shouldered at the summits. They are marked by many fine lines of growth and numerous tine wavy spiral striations. The latter are more regularly developed and distributed than the lines of growth. The periphery of the body whorl
marks the greatest diameter of the shell. The base of the shell, though rather long, falls off rather abruptly at the periphery, then tapers gradually to the anterior end of the columella. It is marked like the spaces between the sutures. The oval aperture
is large. The posterior angle is acute. The outer lip
is decidedly curved, almost patulous, thin. The columella is long, slender, gently curved, and somewhat reflected, provided with a moderately strong, oblique fold near its insertion. The parietal wall lacks a callus.
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 very regular in outline, yellowish white, shining. It measures 4 mm. The 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 almost completely immersed in the first of the succeeding volution. The whorls of the teleoconch are moderately rounded, rather high between the sutures, slightly shouldered at the summits. They are marked by many fine lines of growth and numerous tine wavy spiral striations. The latter are more regularly developed and distributed than the lines of growth. 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...
marks the greatest diameter of the shell. The base of the shell, though rather long, falls off rather abruptly at the periphery, then tapers gradually to the anterior end of the columella. It is marked like the spaces between the sutures. The oval 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 large. The posterior angle is acute. 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 decidedly curved, almost patulous, thin. The columella is long, slender, gently curved, and somewhat reflected, provided with a moderately strong, oblique fold near its insertion. The parietal wall lacks a callus.