''Malea ringens'', common name the grinning 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 ...

, 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 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 e ...

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 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 ...

, the tun shells.

Distribution

This species occurs in the Pacific Ocean from

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

and off Galapagos Islands.

Description

The size of the shell of ''Malea ringens'' varies between 60 mm and 270 mm, with an average diameter of about 100 mm. It is one of the largest of Panamic shells. These shells are basically white and delicately spotted with yellow under the thin periostracum.Angeline Myra Kee
Sea Shells of Tropical West America: Marine Mollusks from Baja California to Peru
/ref> Tonnidae - Malea ringens

The pretty thick shell is ovate-globose and ventricose. The pointed

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 formed 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, the upper of which are slightly convex, but little developed, having three or four transverse striae, very apparent, and spotted with brown blotches. 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 very much inflated, completely surrounded by from fifteen to twenty equal ribs, depressed, but slightly rounded. These ribs are separated from each other by a shallow furrow, which becomes wider between the first two or three upper ribs, by the disappearance of the intermediate ribs. The longitudinal striae of growth are numerous, very fine, and slightly apparent. 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 narrow, for it is much contracted by two protuberances situated upon the two lower thirds of 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 ...

. 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 arched, flattened, widened within, having a wide longitudinal ridge outside of it. It has, on the inside, the whole length, from sixteen to eighteen ridges, or very strongly prominent teeth. The edge is undulated and denticulated. The inner lip is thin, diaphanous, spreading upon the body of the shell, to which it adheres, except towards the base, where it becomes free and thicker. The

is twisted, and presents a very deep emargination, above which is seen a wide, thick, furrowed tubercle, which appears as if suspended over this hollow. Another tubercle projects near the base, separated from the first by the cavity just spoken of. It is furnished with wrinkles and numerous furrows of a brilliant white, which imperceptibly diminish in size at the base, and above the emargination, which is turned out like a gutter, and perfectly smooth. The color of this shell is whitish, slightly blended with a dull yellow. The interior is red. 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 yellowish.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 latilabre'')

References

* Swainson, W. (1822) Appendix: Description of several new shells, and remarks on others, contained in the collection of the late Mrs. Bligh. In: A catalogue of the rare and valuable shells, which formed the celebrated collection of the late Mrs. Bligh. The sale of this collection ... 20 May 1822. C. Dubois, London: appendix, pp. 1–20 page(s): 4

External links

* {{Taxonbar, from=Q6775263 Tonnidae Gastropods described in 1822 Taxa named by William John Swainson