Odostomia gemma
Encyclopedia
Odostomia gemma is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
of the protoconch
are obliquely about half immersed in the first of the later whorls. The six whorls of the teleoconch are flattened, with strong tabulated and crenulated summits. They are crossed by three strong, rounded, subequally spaced, spiral keels and rounded axial ribs between the sutures. The latter extend from the summit to and over the second keel, but not over the sulcus separating this from the third. The junctions of the axial ribs and the spiral keels form strong tubercles. The sulcus between the second and the third keel is deep, decidedly deeper than the peripheral sulcus, both of which, as well as the sulci of the base, are crossed by minute closely placed, axial raised threads. The base of the body whorl
is well rounded, somewhat attenuated. It is marked by live strong, rounded, subequal and subequally spaced spiral keels. The aperture
is oval. The posterior angle is acute. The outer lip
is wavy. The columella is short, curved and slightly revolute. It is provided with a quite strong oblique fold near its insertion. The parietal wall covered by a moderately thick 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 small, white shell grows to a length of 3 mm. It is elongate-conic, slender, slightly umbilicated. The at least two 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 obliquely about half immersed in the first of the later whorls. The six whorls of the teleoconch are flattened, with strong tabulated and crenulated summits. They are crossed by three strong, rounded, subequally spaced, spiral keels and rounded axial ribs between the sutures. The latter extend from the summit to and over the second keel, but not over the sulcus separating this from the third. The junctions of the axial ribs and the spiral keels form strong tubercles. The sulcus between the second and the third keel is deep, decidedly deeper than the peripheral sulcus, both of which, as well as the sulci of the base, are crossed by minute closely placed, axial raised threads. 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...
is well rounded, somewhat attenuated. It is marked by live strong, rounded, subequal and subequally spaced spiral keels. 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 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 wavy. The columella is short, curved and slightly revolute. It is provided with a quite strong oblique fold near its insertion. The parietal wall covered by a moderately thick callus.
Distribution
This marine species occurs in the following locations:- MadagascarMadagascarThe Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
- Southeast AsiaSoutheast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
- JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...