''Tonna dolium'', common name the spotted 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 large

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 ...

or tun snail, 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 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 ...

Tonnidae, the tun shells.Vos, C. (2009). Tonna dolium. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=208012 on 2016-05-22

Description

The size of the shell varies between 100 mm and 181 mm. The thin shell is ovate-globose and ventricose. 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 generally short. It is composed of 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, slightly flattened above. 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 large and very convex. All these whorls are encircled by wide and distant ribs, slightly convex, numbering ten upon the body whorl. Others, more narrow, are placed alternately within the furrows, which are wide and very slightly striated. The surface of this shell is of a white color, slightly grayish, and sometimes rose-colored. It is ornamented upon the ribs, with alternate white and red spots, often also orange, which, disposed thus in regular series, present a beautiful appearance. 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 very large, colored within of a chestnut tint. The outer lip is thin, notched, canaliculated within, and its edge is white and undulated. The inner lip is only slightly perceptible towards the base, where it forms a part of the umbilicus, which is hardly developed. The columella is twisted spirally, and furnished externally, even to the emargination of the base, with longitudinal ribs. Its ribs, wide and distant, its furrows equally wide, render it easily distinguishable.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 maculatum'')

Distribution

This marine species occurs in the Indo-West Pacific off

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

, the Mascarene Basin and off the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

References

* Linnaeus, C. 1758. ''Systemae naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differetiis, synonymis, locis.v. Holmiae'' : Laurentii Salvii 824 pp. * Martini, F.H.W. 1777. ''Neues systematisches Conchylien-Cabinet, fortgesetzt durch Johann Heironymus Chemnitz.'' Nürnberg : G. N. Raspe Vol. 3 vi + 1-434, pls 66-121. * Röding, P.F. 1798. ''Museum Boltenianum sive Catalogus cimeliorum e tribus regnis naturae quae olim collegerat Joa.'' Hamburg : Trappii 199 pp. * Lamarck, J.B.P.A. de M. 1822. ''Histoire naturelle des Animaux sans Vertèbres''. Paris : J.B. Lamarck Vol. 7 711 pp. * Springsteen, F.J. & Leobrera, F.M. 1986. ''Shells of the Philippines''. Manila : Carfel Seashell Museum 377 pp., 100 pls. * Drivas, J.; Jay, M. (1987). ''Coquillages de La Réunion et de l'Île Maurice''. Collection Les Beautés de la Nature. Delachaux et Niestlé: Neuchâtel. . 159 pp. * Wilson, B. 1993. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp. * Vos, C. & Terryn, Y. in Poppe, G.T. & Groh, K. (eds) 2007. ''A Conchological Iconography. The family Tonnidae''. Hackenheim, Germany : ConchBooks pp. 1–121, 63 pls.

External links

World Register of Marine Species entry

Description

Distribution

References

External links

Further reading