''Tonna variegata'', commonly known as the variegated tun, 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 ...

of 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

Tonnidae The Tonnidae are a family (biology), family of medium-sized to very large sea snails, known as the tun shells. These are marine invertebrates, marine gastropod molluscs in the clade Littorinimorpha. The name ''tun'' refers to the snails' shell sh ...

(also known as the tun shells).Vos, C. (2015). Tonna variegata. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=410322 on 2016-05-22 The forma ''Tonna variegata'' f. ''dunkeri'' (Hanley, 1860) is a synonym of '' Tonna dunkeri'' (Hanley, 1860)

Description

The size of the shell varies between 70 mm and 200mm. The thin shell has an ovate-globose, ventricose shape. 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 six convex

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, slightly separated by a shallow suture, and loaded with transverse rounded ribs, which are very approximate. 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 ...

composes, itself, almost the whole of the shell. Twenty to twenty-six transverse ribs may be counted upon its surface, among which, in old specimens, are found other smaller ones which are alternately disposed between the first, towards the most elevated part. All the ribs are separated by furrows which are not throughout of the same size. The

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 wide, large and ovate. Its

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 ...

s are white, and the interior reddish. The outer lip, terminated by a scolloped dilatation, is traversed by a canal of no great depth. The inner lip is white, thin, applied to the body of the body whorl and forms a part of the umbilicus. 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 ...

is twisted spirally. The coloring of the exterior is whitish, varied with red, and covered, upon the transverse ribs, with irregular spots which sometimes form longitudinal or zigzag bands of a deeper color. Upon some specimens are observed ribs which have no other tint of coloring than the ground of the shell. Young specimens are diaphanous and slightly colored by spots. The

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and ...

is thin and reddish.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 'Dolium variegatum'')

Distribution

This marine species occurs off South and Southeast Africa; off

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and off Australia (

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

References

* Lamarck, J.B.P.A. de M. 1822. ''Histoire Naturelle des Animaux sans Vertèbres.'' Suite des Gastéropodes. Paris : J.B. Lamarck Vol. 6(2) 232 pp. * Philippi, R.A. 1847. ''Abbildungen und Beschriebungen neuer oder wenig gekannter Conchylien.'' Cassel : Theodor Fischer Vol. 3 pp. 1–50. * Hanley, S. 1860. ''Systematic list of the species of Dolium restricted.'' Proceedings of the Zoological Society of London 27: 487-493 * Hedley, C. 1919. ''A review of the Australian Tun Shells.'' Records of the Australian Museum 12(11): 329-336, pls 39-44 * Kilias, R. 1962. ''Gastropoda/Prosobranchia. Tonnidae''. Das Tierreich 77: 1-63 Gastropods.com: ''Tonna (Variegata complex) variegata''
{{Taxonbar">from=Q14496708 Tonnidae Gastropods described in 1758 Taxa named by Carl Linnaeus