Linopyrga tantilla
Encyclopedia
Linopyrga tantilla is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
are small, strongly obliquely immersed in the first post-nuclear whorl, only a portion of the last solution is visible. The seven post-nuclear whorlsare strongly shouldered, moderately rounded, rather high between the sutures, and appearing somewhat constricted at this point. They are marked by strong, rounded, backward slanting axial ribs, which render the summits of the whorls strongly crenulate. Fourteen of these ribs occur upon the second, twenty-three upon the fourth, and thirty-two upon the penultimate whorl. The intercostal spaces are about twice as wide as the ribs, crossed between the sutures by five subequally spaced, raised spiral threads, the posterior one of which is a little farther from the summit than it is from its adjacent fellow; it is also a little less .strongly
developed than the rest. The ribs and spiral threads thus form a series of meshes or reticulations. The periphery and base of the body whorl
are well rounded, sculptured
, like the spaces between the sutures, by the axial ribs which continue prominently to the narrow umbilicus, and six subequal and subequally spaced spiral threads, with an indication of a very weak seventh within the narrow umbilicus. The ovoid aperture
is moderately large. The posterior angle is obtuse. The outer lip
is strong. The columella is slender, decidedly curved, and somewhat revolute, with a prominent oblique fold near its insertion The parietal wall is covered by a very strong callus, which gives the periostracum
a complete 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, slender shell measures 2.6 mm. It is turrited, milk-white. 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 small, strongly obliquely immersed in the first post-nuclear whorl, only a portion of the last solution is visible. The seven post-nuclear whorlsare strongly shouldered, moderately rounded, rather high between the sutures, and appearing somewhat constricted at this point. They are marked by strong, rounded, backward slanting axial ribs, which render the summits of the whorls strongly crenulate. Fourteen of these ribs occur upon the second, twenty-three upon the fourth, and thirty-two upon the penultimate whorl. The intercostal spaces are about twice as wide as the ribs, crossed between the sutures by five subequally spaced, raised spiral threads, the posterior one of which is a little farther from the summit than it is from its adjacent fellow; it is also a little less .strongly
developed than the rest. The ribs and spiral threads thus form a series of meshes or reticulations. The periphery and 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, sculptured
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
, like the spaces between the sutures, by the axial ribs which continue prominently to the narrow umbilicus, and six subequal and subequally spaced spiral threads, with an indication of a very weak seventh within the narrow umbilicus. The ovoid 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 moderately large. 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 strong. The columella is slender, decidedly curved, and somewhat revolute, with a prominent oblique fold near its insertion The parietal wall is covered by a very strong callus, which gives the periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
a complete appearance.