''Antisolarium egenum'' is a small

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 ...

mollusc 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 esti ...

in the family Trochidae, the top shells.Bieler, R. (2014). Antisolarium egenum. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=567708 on 2014-06-19

Description

The size of the shell varies between 4 mm and 7.5 mm. The thin, minute shell has a low ovate-conic shape and is amply umbilicated. Its color is ashy white, pearly beneath. The six

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 are convex. 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 obtusely angular. Each whorl is encircled by four sharply-compressed well-elevated ribs, the two uppermost of which are beaded. The interspaces are concave, smooth, with a single groove near the margin of the umbilicus. The latter occupies ⅓ of the base, is tunnel-shaped and penetrates to the apex. Its sides are excavated on each whorl, the verge of which is crenulated. The aperture is nearly circular, slightly encroached upon by the inflection of the columella. Its interior is pearly. The lip simple.H. Pilsbry, Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This marine species is endemic to New Zealand.

References

* Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 * Herbert D.G. (1992). ''Revision of the Umboniinae (Mollusca: Prosobranchia: Trochidae) in southern Africa and Mozambique''. Annals of the Natal Museum 33(2):379-459.

External links

* {{Taxonbar, from=Q1056626 egenum Gastropods of New Zealand Gastropods described in 1849