Syrinx aruanus
Syrinx aruanus, common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 the Australian trumpet or false trumpet, is a species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of extremely large sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

 measuring up to 91 cm long and weighing up to 18 kg. It is a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusk in the family Turbinellidae
Turbinellidae are a family of sea snails, marine gastropod mollusks in the order Neogastropoda.-Distribution:Species in this family are found world-wide, mostly in tropical shallow waters but some in deep waters.- Subfamilies :...

, and is the only species in the genus Syrinx.

This is the largest living snail (shelled gastropod) species in the world, and arguably the largest (heaviest) gastropod in the world. Although the shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 itself is quite well known to shell collectors because of its extraordinary size, little is known about the ecology and behavior of the species, except for one study about its feeding habits.


In 1681, Filippo Bonanni
Filippo Bonanni
Filippo Bonanni or Buonanni was Italian Jesuit scholar, born in Rome. Among his many works of erudition are the two-volume Numismata Pontificum Romanorum in , and the Gabinetto Armonico in 1723, a splendid collection of 150 engravings of musical instruments from around the world.-Scientific...

 depicted this species in the first book ever published that was solely about seashells. The book was entitled: Ricreatione dell' occhio e dela mente nell oservation' delle Chiociolle, proposta a' curiosi delle opere della natura, &c.

The taxonomic affinities of Syrinx aruanus were not properly understood for a long time. Until fairly recently it was placed in the family Melongenidae
Melongenidae, the crown conchs, busycon whelks and their relatives, are a taxonomic family of large to very large marine gastropods in the clade Neogastropoda.- Taxonomy :Genera Busycon and Busycotypus were placed in Melongenidae...

. A detailed taxonomic
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 overview of this species was provided by Harasewych & Petit (1989).


This is the largest Recent (as opposed to fossil) shelled gastropod, and the largest shelled gastropod by weight. (However, the largest shell-less gastropod or slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

 is Aplysia vaccaria
Aplysia vaccaria
Aplysia vaccaria, also known as the "black sea hare," and the "California black sea hare," is a species of extremely large sea slug, a marine, opisthobranch, gastropod mollusk in the family Aplysiidae. It is the largest known species of sea slug, and may be the world's largest living gastropod. -...

, a giant sea hare
Sea hare
The clade Aplysiomorpha, commonly known as Sea hares or Sea Bags , are medium-sized to very large Opisthobranchia with a soft internal shell made of protein...

 known as the California black sea hare. The largest A. vaccaria has been measured at 99 cm in length, making it the longest gastropod, and weighing in at almost 14 kg.) An extremely large species of fossil gastropod is Campanile giganteum
Campanile giganteum
†Campanile giganteum is a species of exceptionally large fossil sea snails, marine gastropod molluscs in the family Campanilidae. This species dates from the Eocene epoch. With a shell length of 40 to 60 cm this is considered to be one of the largest species of shelled gastropod that ever lived...


The overall height (also known as length) of the shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 of S. aruanus is up to 91 cm (see also Hawaiian Shell News, 1982). The weight of the shell is about 1800 g.

The shell is usually pale apricot
The apricot, Prunus armeniaca, is a species of Prunus, classified with the plum in the subgenus Prunus. The native range is somewhat uncertain due to its extensive prehistoric cultivation.- Description :...

 in color, however in life it is covered by thick brown or grey periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...

. The shell color can fade to a creamy yellow.The whole shell has a spindle
Spindle (textiles)
A spindle is a wooden spike used for spinning wool, flax, hemp, cotton, and other fibres into thread. It is commonly weighted at either the bottom middle or top, most commonly by a circular or spherical object called a whorl, and may also have a hook, groove or notch, though spindles without...

-like shape. The spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

 of the shell is high. The whorls usually have a strong keel which can have nodules on it. The shell has a long siphonal canal
Siphonal canal
Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure...

. There are no folds on the columella, unlike some other genera within the same family.

Juvenile shells show a long tower-shaped protoconch
A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...

 or embryonic shell of 5 whorls, which is usually lost in the adult. This protoconch is about 2.5 cm long and looks so unlike the adult shell that it was described by George Washington Tryon
George Washington Tryon
George Washington Tryon, Jr. was an American malacologist who worked at the Academy of Natural Sciences in Philadelphia.- Biography :George Washington Tryon was the son of Edward K. Tryon and Adeline Savidt...

 in 1887 as a different species.

The weight of the animal (including the shell) can be up to 18 kg (40 lb). The radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

 of this species was described in detail by Wells et al. (2003).


This species occurs in the northern half of Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and adjacent areas, including eastern Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

 and Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...



These giant snails live on sandy bottoms in the intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...

 and the sublittoral down to about 30 m. Where it has not been overfished, this snail is locally common. (Abbott & Dance, 1982)

This carnivorous species is specialized for feeding on polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...

 worms in the genera Polyodontes (Acoetidae), Loimia (Terebellidae
Terebellidae is a family of polychaete worms. They are surface deposit feeders, catching falling particles with numerous elongate prostomial tentacles splayed out on the sea floor. These tentacles, which are the most or only normally visible portion of the animal and are reminiscent of spaghetti,...

) and Diopatra (Onuphidae). It may seem unlikely for such a large gastropod to feed on worms, but worms in the family Acoetidae do include the largest polychaetes, with a length of over 1 meter. These worms live in tubes; Syrinx aruanus can reach them with its proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...

, which has a length of up to 250 mm.

Human uses

This species is fished both for its very large shell and for its edible flesh, which is sometimes used as bait. The shell is sold for shell collections and is used as a source of lime. Another use of its shell is as a water carrier.
The indigenous peoples of Australia who live on the Pennefather River
Pennefather River
The Pennefather River in Queensland, Australia, is located on western Cape York Peninsula at . The river is about 11 km long and up to about 2km wide.- External links :**...

 in Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

, use (or used) a half-moon shaped nose-pin known as an imina which is made from the shell of Syrinx aruanus. This nose pin is employed by men only; the women use a piece of grass instead. In order to make one of these nose pins, if the Syrinx shell is fresh, then it can be worked on right away, but if it is dried out, the shell is first soaked for two or three days in water. After this, a portion of the shell which is near the suture and the keel on the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...

 is chipped out using a stone, (see image), and then is ground down with water. The resulting rib-shaped object is used as the nose-pin.

See also

  • Pleuroploca gigantea
    Pleuroploca gigantea
    Pleuroploca gigantea, common name the Florida horse conch, is a species of extremely large predatory subtropical and tropical sea snail, a marine gastropod mollusk in the family Fasciolariidae, the spindle snails, tulip snails and their allies....

    , the largest living sea snail species in the Americas
  • Aplysia vaccaria
    Aplysia vaccaria
    Aplysia vaccaria, also known as the "black sea hare," and the "California black sea hare," is a species of extremely large sea slug, a marine, opisthobranch, gastropod mollusk in the family Aplysiidae. It is the largest known species of sea slug, and may be the world's largest living gastropod. -...

    , the largest shell-less gastropod, and the longest gastropod

Further reading

  • Kesteven H. L. (1904). "The anatomy of Megalatractus". Memoirs of the Australian Museum 4: 419–449.
  • (1982). "Large Syrinx aruanus of shell length 36 inches (91.4cm) illustrated". Hawaiian Shell News 30(7): 12.

External links

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