''Mangelia robusticostata'' 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 Mangeliidae.
[WoRMS (2009). Cytharella robusticostata (E. A. Smith, 1879). In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://marinespecies.org/aphia.php?p=taxdetails&id=433485 on 2017-09-21]
Description
The length of the shell attains 6.3 mm, its diameter 2.5 mm.
(Original description) The shell is ovately fusiform. The color is light brown, whitish at the base of the body whorl and outer lip. It contains 6 whorls with 1½ whorls in the
apex. The succeeding whorls form 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 ...
, globose, large, smooth. The subsequent whorls are turreted, angulated at the upper part at a short distance from the suture, beneath the angulation, which is rounded, sloping inward, so that they are much narrower at the lower part than at the angle, obliquely costate, and striated by the incremental lines. The ribs are very thick (12 on the penultimate whorl), subacute at their edge, and almost adjacent to one another at their bases, thinner and at times sublamellar at the upper extremities, and very obliquely flexuous from the angle downwards. On the last whorl they gradually become obsolete below the middle. The
aperture is small, livid brown within, except near the lip, where it is whitish. The outer lip is thin at the extreme edge, strengthened exteriorly by the last well-developed rib, which is white with a single livid-brown spot a little below the middle. The sinus is scarcely discernible. The
columella is smooth, slightly oblique, subrectilinear, covered with a thin callosity which unites at the upper extremity with the termination of the outer lip. 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 very short.
The whorls are turreted, with a strongly angular periphery. They show twelve short, oblique ribs. The outer
lip is thin at the edge, but thickened externally by one of the ribs. The sinus is scarcely discernible. The color of the shell is yellowish brown, whitish towards 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 ...
and outer lip.
G.W. Tryon (1884) Manual of Conchology, structural and systematic, with illustrations of the species, vol. VI; Philadelphia, Academy of Natural Sciences
Distribution
This marine species was found 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
Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295
{{DEFAULTSORT:Mangelia Robusticostata
robusticostata
Gastropods described in 1879