''Mitromorpha multigranosa'' is a species of
sea snail
Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...
, a marine
gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Mitromorphidae
Mitromorphidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Mitromorphidae Casey, 1904. In: MolluscaBase (2018). Accessed through: World Register of Marin ...
.
Description
The length of the shell attains 4.3 mm, its diameter is 2. mm.
The small shell has a fusiform-ovate shape. Its color varies from blackish to reddish with a white zone above the middle of the whorl. It is ornated everywhere with white or blackish to reddish granules. The shell has 5½
whorl
A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs).
Whorls in nature
File:Photograph and axial plane floral ...
s, of which 2½ smooth whorls in the
protoconch
A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...
. They are at the top concave and carinated, the others are rather flat. The ribs are crossed by 14 spiral lirae. The ribs and the lirae are so near
together that the granules almost touch one another. The narrow
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An opt ...
measure about ½ the total length. The
columella is straight and shows two-minute tubercles in the middle. and has a narrow callus. The outer
lip is hardly incrassate and is slightly sinuate at the top.
Smith E.A. (1890). Report on the marine molluscan fauna of the island of St. Helena. Proceedings of the Zoological Society of London. 1890: 247–317, pl. 21–24
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Distribution
This species occurs in the Atlantic Ocean off St. Helena
Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constitu ...
.
References
External links
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{{DEFAULTSORT:Mitromorpha Multigranosa
multigranosa
Gastropods described in 1890