Miralda diadema
Encyclopedia
Miralda diadema is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
decidedly tabulated. The two helicoid whorls of the protoconch
are moderately large, and about one-third immersed in the later whorls. The five whorls of the teleoconch are moderately rounded, decidedly tabulated at the summit,. They are ornamented by rounded, axial ribs which quickly diminish in strength as they pass from the summit of the whorls to the periphery. Sixteen of these ribs occur upon the second, and twenty upon the penultimate whorl. The ribs are thickened at the anterior termination of the shoulder and render it decidedly crenulated. The intercostal spaces are a little wider than the ribs. In addition to the axial ribs the whorls are marked by strong spiral cords, two of which can be seen between the sutures on the first and second and four and one-half upon the penultimate whorl. The junction of the posterior one of these two cords and
the axial ribs form a series of tubercles. The anterior cord is only slightly tuberculated, the ribs extending only feebly to it. The periphery and the base of the body whorl
are well rounded, the latter decidedly attenuated and marked by seven subequal and subequally spaced spiral keels. The suboval aperture
is large. The posterior angle is very obtuse. The outer lip
is thick. The columella is re-enforced by the attenuated base, curved. It is provided with a conspicuous obliquie fold near its insertion. The parietal wall is 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 white, small shell grows to a length of 1.8 mm. It is subovate, minutely umbilicated, with the summits of 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...
decidedly tabulated. The two helicoid whorls 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 moderately large, and about one-third immersed in the later whorls. The five whorls of the teleoconch are moderately rounded, decidedly tabulated at the summit,. They are ornamented by rounded, axial ribs which quickly diminish in strength as they pass from the summit of the whorls to the periphery. Sixteen of these ribs occur upon the second, and twenty upon the penultimate whorl. The ribs are thickened at the anterior termination of the shoulder and render it decidedly crenulated. The intercostal spaces are a little wider than the ribs. In addition to the axial ribs the whorls are marked by strong spiral cords, two of which can be seen between the sutures on the first and second and four and one-half upon the penultimate whorl. The junction of the posterior one of these two cords and
the axial ribs form a series of tubercles. The anterior cord is only slightly tuberculated, the ribs extending only feebly to it. 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, the latter decidedly attenuated and marked by seven subequal and subequally spaced spiral keels. The suboval 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 very 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 thick. The columella is re-enforced by the attenuated base, curved. It is provided with a conspicuous obliquie fold near its insertion. The parietal wall is covered by a moderately thick callus.