''Pilsbryspira umbrosa'' 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

Pseudomelatomidae Pseudomelatomidae is a family of predatory sea snails, marine gastropods included in the superfamily Conoidea (previously Conacea) and part of the Neogastropoda ( Bouchet & Rocroi, 2005). In 1995 Kantor elevated the subfamily Pseudomelatomina ...

Description

The length of the shell attains 12 mm, its diameter 4 mm. (Original description) The small, narrow shell has a fusiform shape and is of rude sculpture. It is dusky-brown with a rufous tinge over 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 orifice. The shell contains 7-8

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 nepionic being imperfect in the specimens seen), the remainder longitudinally furnished with obtusely-rounded, strong, and frequent ribs, say about fourteen on the body whorl. All the whorls are ventricose, impressed, and spirally plainly ridged suturally, and crossed by strongly developed spirals, swollen and almost becoming nodulous at the points of junction with the costae. The aperture is small and ovate. The outer lip is slightly expanded. The sinus is wide but shallow. 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 columellar margin is oblique. Proceedings of the Malacological Society of London v. 14-15 (1920-1923)
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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

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295
umbrosa Gastropods described in 1923 {{Pseudomelatomidae-stub