''Parthenina meta '' 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
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
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* ...
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 Pyramidellidae, the pyrams and their allies.
[Dall & Bartsch, ''Notes on Japanese, Indo-Pacific and American Pyramidellidae''; Proceedings of the U.S. National Museum, vol XXX n° 1452; 1906]
Description
The thin, milk-white shell is very small, measuring 2.9 mm. It is turreted, with channeled
sutures and an obtuse
apex. The nuclear
whorls
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 d ...
are small, strongly obliquely immersed in the first post-nuclear whorl; only a portion of the last volution is visible. The six post-nuclear whorls overhang somewhat. They are rather high between the sutures, shouldered at the summit, flattened, suddenly contracted below the periphery. The summits of succeeding whorls fall considerably anterior to the periphery, which appears decidedly angular. The whorls are marked by strong axial ribs which extend undiminished over the angular periphery and the base of 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 ...
to the umbilical region. Sixteen of these ribs occur upon the second, twenty-two upon the fourth and the penultimate whorl. The ribs are slightly constricted just below the summit, which gives them a beaded appearance. The intercostal spaces are about twice as wide as the ribs, crossed by two closely placed, raised spiral threads, the anterior one of which marks the angulation of the periphery. The junction of ribs and the spiral threads is subnodulose. The base of the shell is moderately long, narrowly
umbilicate. The
aperture is suboval. The posterior angle is obtuse. The
outer lip is rather thick. The
columella is strongly curved, with a prominent oblique fold near its insertion. The parietal wall is covered with a heavy callus, which gives the periostracum a completed aspect.
Distribution
This species occurs in the Pacific Ocean 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
* Higo, S., Callomon, P. & Goto, Y. (1999) ''Catalogue and Bibliography of the Marine Shell-Bearing Mollusca of Japan''. Elle Scientific Publications, Yao, Japan, 749 pp.
Systax : ''Odostomia meta''
External links
{{Taxonbar, from1=Q61686447, from2=Q7078195
meta
Meta (from the Greek μετά, '' meta'', meaning "after" or "beyond") is a prefix meaning "more comprehensive" or "transcending".
In modern nomenclature, ''meta''- can also serve as a prefix meaning self-referential, as a field of study or ende ...
Gastropods described in 1906