''Microdrillia niponica'' 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 ...

Borsoniidae Borsoniidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Borsoniidae. Accessed through: World Register of Marine Species at http://www.marinespecies.o ...

.WoRMS (2015). Microdrillia niponica (E. A. Smith, 1879). In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://marinespecies.org/aphia.php/aphia.php?p=taxdetails&id=434404 on 2016-03-16

Description

The length of the shell attains 7 mm; its width 2 mm.. (Original description) The shell has a shortly fusiform shape and is light brown. It contains 6 ½

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. The nucleus consists of 1½ rather large, globose, glassy shining whorls. The four whorls following are strongly keeled around the middle, concave above, with two or three fine spiral lirae, and also concave below the carina, margined at the upper and lower boundaries by a fine thread-like lira arcuately or flexuously elevately striated above the carina, and obliquely but in an opposite direction, beneath it. The

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

is encircled beneath the principal keel by about ten lirae, whereof the uppermost is the stoutest, the rest gradually becoming finer towards the base. The interstices between them crossed by elevated striae or lines of increment. The

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 ...

is small, brownish, occupying about three-sevenths of the entire length of the shell. Its slit is situated in the concavity above the principal carination. The columella is a little convex or prominent in the middle, and oblique below it. The

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

is short and scarcely recurved.Smith, Edgar A. "11. On a Collection of Mollusca from Japan." Proceedings of the Zoological Society of London. Vol. 47. No. 1. Blackwell Publishing Ltd, 1879.
(described as ''Pleurotoma difficilis'')

Distribution

This marine species occurs off

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

References

External links

Bouchet P., Kantor Yu.I., Sysoev A. & Puillandre N. (2011) A new operational classification of the Conoidea. Journal of Molluscan Studies 77: 273–308
* {{DEFAULTSORT:Microdrillia Niponica niponica Gastropods described in 1879