Triplofusus Giganteus

''Triplofusus giganteus'', commonly known as the Florida horse conch, or the giant horse conch, is a species of extremely large predatory subtropical and tropical sea snail, a marine gastropod mollusc in the family Fasciolariidae, the spindle snails, tulip snails and their allies.Rosenberg, G. (2018). ''Triplofusus giganteus'' (Kiener, 1840). In: MolluscaBase (2018). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=420051 on 2021-07-02 On average, it weighs over .

Although known as a horse conch, this is not a true conch, as it is not in the family Strombidae.

With a shell length that can reach , this species is the largest gastropod in United States waters,Leal, J.H. (2002). Gastropods. p. 99-147. In: Carpenter, K.E. (ed.). The living marine resources of the Western Central Atlantic. Volume 1: Introduction, molluscs, crustaceans, hagfishes, sharks, batoid fishes, and chimaeras. FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists Special Publication No. 5. 1600p. tp://ftp.fao.org/docrep/fao/009/y4160e/y4160e08.pdf PDF/ref> and one of the largest gastropods in the world.

Taxonomy

''Triplofusus giganteus'' was named by Louis Charles Kiener in 1840, originally as ''Fasciolaria gigantea''. The species was subsequently assigned to ''Pleuroploca''. The genus name ''Triplofusus'' was proposed for it in 1953. ''T. giganteus'' has also been known by the name ''Fasciolaria papillosa'', which was named by George Brettingham Sowerby I in 1825, but it is impossible to confirm what species this name originally applied to, due to the brevity of the original description and loss of the type specimen.

Distribution

This large sea snail is found along the Atlantic coast of the Americas from the U.S. state of North Carolina to the north, to Yucatán in the Gulf of Mexico to the south.

Anatomy

''Triplofusus giganteus'' is the largest species of snail in North America. It has been hypothesized that female individuals reach larger sizes than males.
The animal can retract the soft parts entirely into the shell and close it with the operculum. The soft parts are bright orange in color.

Shell

The largest known specimen of ''Triplofusus giganteus'' had a shell long. However, populations have declined in size in recent years due to overharvesting; the largest individuals observed in various recent surveys have had shells ranging from .

The outline of the shell is somewhat fusiform, with a long siphonal canal, and having up to 10 whorls. Its sculpture present several spiral cords and axial ribs, some of which can form knobs on the whorls' shoulders.

The shell color is bright orange in very young individuals. The shell often becomes greyish white to salmon-orange when adult, with a light tan or dark brown periostracum.

Ecology

Habitat

This species dwells on sand, weed, and mud flats from the low intertidal to shallow subtidal zones, in 20 foot (6 m) deep water. They are found at depths ranging from 0 to 100 m.

Feeding habits

''Triplofusus giganteus'' is a predator, with a diet that consists primarily of large gastropods, such as tulip shell ('' Fasciolaria tulipa''), the lightning whelk ('' Sinistrofulgur perversum''), and the queen conch (''Lobatus gigas'') as well as some ''Murex'' species.Wells F. E., Walker D. I. & Jones D. S. (eds.) (2003)
''Food of giants – field observations on the diet of Syrinx aruanus (Linnaeus, 1758) (Turbinellidae) the largest living gastropod''
The Marine Flora and Fauna of Dampier, Western Australia. Western Australian Museum, Perth. ''T. giganteus'' rarely eats bivalves, even when they are readily available, with the exception of pen shells in the genus ''Atrina'', which can comprise 20% of its diet. It has been observed (in an aquarium setting) to eat small hermit crabs of the species ''Clibanarius vittatus''. Cannibalism has been documented in captive ''T. giganteus'', but only seems to occur in individuals that have been deprived of sufficient food.

Reproduction

Female ''T. giganteus'' probably attain reproductive maturity at an age of six or seven years and shell length of 200 to 250 mm. In a single spawning event, a female can lay up to 400 egg capsules, each of which can contain 70 offspring. However, spawning events are infrequent and individuals probably only live a few years after attaining reproductive maturity.

Predators

''T. giganteus'' are commonly eaten by tiger sharks.

Parasites

Parasites of ''Triplofusus giganteus'' include trematode '' Lophotaspis vallei''.

Human use

Modern times

The U.S. state of Florida declared it the state seashell in 1969. The shell is popular with shell collectors partly because of its great size.

Archaeological and anthropological uses

In classic Mayan art, the Horse Conch is shown being utilised in many ways including as paint and ink holders for elite scribes, and also as a bugle or trumpet.

In southern Florida, Native Americans, including the Calusa and Tequesta, used the horse conch to make several types of artifact. The whole shell, or more commonly only the columella, was attached to a wooden handle and used as a hammer or woodworking tool. The body whorl was used as a drinking cup. The columella was also used to make plummets or sinkers.

Conservation

Populations of ''T. giganteus'' are in decline, and because of the rarity of their spawning events they are vulnerable to population collapse.

References

Works cited

*
*
*
*
*
*
*

* Rosenberg, G. 1992. ''Encyclopedia of Seashells''. Dorset: New York. 224 pp. page(s): 91

{{Taxonbar, from=Q140046

Fasciolariidae
Symbols of Florida
Gastropods described in 1825
Taxa named by George Brettingham Sowerby I
Molluscs of the Atlantic Ocean