''Mitromorpha commutabilis'' 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 in the family

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 ...

.MolluscaBase (2018). Mitromorpha commutabilis (E. A. Smith, 1890). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=555868 on 2018-03-15

Description

The length of the shell attains 4 mm, its diameter 1.5 mm. (Original description) This species is very distinctly characterized by its ovate-fusiform form and the coarse style of its sculpture. The longitudinal ribs and the twelve transverse lirae are about equally thick, produced into acute nodules at the points of intersection, and the quadrate interstices are very deeply pitted. The shell contains 5½ slightly convex

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, including 1½ vitreous whorl 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 ...

. The small aperture is narrow. The outer lip is slightly incrassate. The wide siphonal canal is very short. The small sinus is inconspicuous. The columella is upright and shows two tubercles in the middle.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

* {{DEFAULTSORT:Mitromorpha Commutabilis commutabilis Gastropods described in 1890