''Falsimargarita iris'' 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 * Marine habitats * Marine life * Marine pollution Military * ...

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 Calliostomatidae.Bouchet, P. (2012). ''Falsimargarita iris'' (E.A. Smith, 1915). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=567186 on 2012-12-07

Description

The height of the shell attains 20 mm. The thin, whitish,

opalescent Opalescence refers to the optical phenomena displayed by the mineraloid gemstone opalopalescent. 2019. In Noah Webster's 1828 American Dictionary of the English Language. Retrieved January 7, 2019, from https://1828.mshaffer.com/d/word/opale ...

shell has a depressed turbinate shape. It is narrowly umbilicate. It contains 5

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 apical whorls is smooth, glossy, rounded and opaque white. The other whorls are rather convex. They are ornamented with spiral thread-like cords, four on the second whorl. about six or seven on the next, eight or nine on the penultimate whorl, and about forty on 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 ...

. The threads vary in thickness, some being very much more slender than the others. The body whorl is obtusely subangled at the periphery. In the umbilical region it is opaque white and smooth except for some growth lines. The whole surface of the shell exhibits curved lines of growth, but they are not strong enough to make the spiral lirae distinctly granose. The large aperture is subcircular and pearly within. The outer lip is thin. The white columella is obliquely arcuate, thickened, reflexed, and appressed to the umbilical region. This last characteristic is a peculiar feature. Smith, E. A. 1915. Mollusca. Part I.--Gastropoda Prosobranchia, Scaphopoda, and Pelecypoda. British Antarctic ("Terra Nova") Expedition, 1910. Natural History Report. Zoology 2: 61-112, pls. 1-2. British Museum (Natural History): London
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Distribution

This marine species occurs in the Atlantic Ocean off Argentina and the Falkland Islands at depths between 10 m and 461 m.

References

External links

To Biodiversity Heritage Library (4 publications)

To USNM Invertebrate Zoology Mollusca Collection

To World Register of Marine Species
* {{Taxonbar, from=Q5432782 iris Gastropods described in 1915 Molluscs of the Atlantic Ocean