Odostomia callimorpha
Encyclopedia
Odostomia callimorpha is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
are completely immersed. The five post-nuclear whorls are flattened, slightly contracted at the sutures, moderately shouldered at the summit. They are marked by strong, depressed, rounded, almost vertical axial ribs, of which 22 occur upon all but the first whorl, which is smooth. The intercostal spaces are about as wide as the ribs, crossed by three slender, spiral lirations on the anterior half of the whorls between the sutures. The sutures are subchanneled. The periphery and the base of the body whorl
are well rounded, and marked by the continuations of the axial ribs, which extend almost undiminished to the umbilical area and five equal slender, spiral lirations on the posterior half of the base. The aperture
is broadly oval. The posterior angle is acute. The outer lip
is thin, showing the external sculpture within. The columella is strongly curved, slightly revolute, reenforced on its posterior half by the base, provided with a strong 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 very small, pupiform shell is milk-white. It measures 1.5 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 completely immersed. The five post-nuclear whorls are flattened, slightly contracted at the sutures, moderately shouldered at the summit. They are marked by strong, depressed, rounded, almost vertical axial ribs, of which 22 occur upon all but the first whorl, which is smooth. The intercostal spaces are about as wide as the ribs, crossed by three slender, spiral lirations on the anterior half of the whorls between the sutures. The sutures are subchanneled. The periphery and the base 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...
are well rounded, and marked by the continuations of the axial ribs, which extend almost undiminished to the umbilical area and five equal slender, spiral lirations on the posterior half of the base. 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 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 thin, showing the external sculpture within. The columella is strongly curved, slightly revolute, reenforced on its posterior half by the base, provided with a strong fold at its insertion.