''Nassarius distortus'', common name : the distorted nassa, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Nassariidae The Nassariidae, Nassa mud snails (USA), or dog whelks (UK), are a taxonomic family of small to medium-sized sea snails, marine gastropod mollusks in the clade Neogastropoda. "Dog whelk" also refers to ''Nucella lapillus''. Shell description T ...

, the Nassa mud snails or dog whelks.

Description

The shell size varies between 18 mm and 35 mm The ovate, conical shell is smooth, polished, and whitish. A decurrent band of a rose color is seen beneath the suture, and three others surround the middle of the lowest

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 ...

. That of the middle is broader and more apparent. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

is composed of seven slightly convex whorls, ornamented with longitudinal ribs formed like folds, numerous and slightly elevated. The upper edge of the whorls is a little flattened. The base of the lowest is accompanied with two distinct ridges. The suture is edged with rounded tubercles situated between each fold, where they form a sort of necklace. The white

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is ovate, contracted above by a transverse fold of the callosity. The outer

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

is subtruncated, somewhat denticulated upon the lower edge, and marked with transverse striae internally. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

edge is covered by a pretty thick callosity, spreading a little upon the belly of the shell.Kiener (1840). General species and iconography of recent shells : comprising the Massena Museum, the collection of Lamarck, the collection of the Museum of Natural History, and the recent discoveries of travellers; Boston :W.D. Ticknor,1837
(described as ''Buccinum monile'')

Distribution

This marine species has a wide distribution in the Indo-West Pacific; also occurs off Australia (

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

)

References

* Adams, A. 1852. ''Catalogue of the species of Nassa, a genus of Gasteropodous Mollusca, belonging to the family Buccinidae, in the Collection of Hugh Cuming, Esq., with the description of some new species.'' Proceedings of the Zoological Society of London 1851(19): 94–112 * Reeve, L.A. 1853. ''Monograph of the genus Nassa.'' pls 1–25 in Reeve, L.A. (ed). Conchologia Iconica. London : L. Reeve Vol. 8. * Dautzenberg, Ph. (1929). ''Mollusques testacés marins de Madagascar''. Faune des Colonies Francaises, Tome III * Cernohorsky W. O. (1984). ''Systematics of the family Nassariidae (Mollusca: Gastropoda).'' Bulletin of the Auckland Institute and Museum 14: 1–356 * Wilson, B. 1994. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, WA : Odyssey Publishing Vol. 2 370 pp.

External links

* {{Taxonbar, from=Q6967449 Nassariidae Gastropods described in 1852