Large fencing snail

from Wikipedia, the free encyclopedia
Large fencing snail
Large fencing snail surrounded by thalassia. The edge of the mouth ("wing") has broken off.

Large fencing snail surrounded by thalassia . The edge of the mouth ("wing") has broken off.

Systematics
Subordination : Hypsogastropoda
Partial order : Littorinimorpha
Superfamily : Stromboidea
Family : Strombidae
Genre : Lobatus
Type : Large fencing snail
Scientific name
Lobatus gigas
( Linnaeus , 1758)
Male of Strombus gigas (= Lobatus gigas ), with claw-like operculum . The penis protrudes from the house on the left. Chenu , 1844
Antennae of the fencer with eye
Fencing snail lying in the sand
A Pleuroploca gigantea eats a large fencing snail, Dry Tortugas National Park , Florida, June 2010.
Thousands of housings of Lobatus gigas , thrown away after their meat has been eaten
Shell of the great fenugreek ( Lobatus gigas ) from all sides
Housing of Lobatus gigas

The great fenugreek or giant wing snail ( Lobatus gigas or Eustrombus gigas , formerly Strombus gigas ) is a Caribbean sea ​​snail and the largest representative of the fenugreek . It is the second largest species of the winged snail and one of the largest ever species .

features

The shell of the adult snail measures 15 to 31 cm and has a protruding mouth rim ("wing"). The house is top-shaped with a very bulbous body, furrowed across and wrinkled. The circumferences of the thread and the circumference of the body are occupied by conical, protruding pins towards the tip of the housing. The coloration varies considerably. The basic color is white, in the area of ​​the mouth rose-red.

The anatomy of the great fencer was first described in more detail by Colin Little in 1965 and Luiz RL Simone in 2005.

The snail has a strongly extendable proboscis , at the base of which the two antennae sit. At the tip of each antenna there is a lenticular eye with a black pupil and a yellow iris , and below each a smaller, short sensory antenna branches off. The antennae and the lens eyes are regenerated if they are lost .

The animal has a large and strong foot. At the bottom of its front end there is a pit with the gland secreting mucus. At the rear end on about a third of the foot is the horny, claw-shaped operculum reinforced by a central rib , with the help of which the snail can move jerkily and without a trace of mucus through contractions of the foot. When crawling, only the front third of the foot touches the ground, because behind it the foot has a round cross-section.

The flesh-colored coat is dark in color in the front and lighter in the back, fading into gray. The hem of the coat, like the sipho , is usually orange or yellow. The foot is spotted brown at the edge and merges into white towards the viscera. The head and the antennae have particularly dark spots.

Life cycle

The females of this species are usually larger than the males, with both sexes each making up about half of the individuals. The snails reach sexual maturity at the age of around 3 to 4 years with a shell length of around 18 cm and a body mass of around 2.5 kg, when the wing at the mouth of the shell is already fully developed. They live up to 7 years in shallow water and around 20 to 30 years in deeper water, and up to 40 years according to some estimates. Usually several males mate a female, using a long penis . Between March and October, the female snail lays around 8 to 9 gelatinous cords, which can be up to 23 m long and each contain around 180,000 to 460,000, sometimes up to 750,000 eggs that have different fathers. After about 5 days, Veliger larvae emerge from the eggs and live pelagically on phytoplankton for about 16 to 40 days . The metamorphosis takes place with a case length of about 1.2 mm. The young snails usually spend their first year of life buried in the sand. Like other fencer snails , Lobatus gigas undergoes a considerable change in shape in the course of its life even after the actual metamorphosis and only develops its "wing" as an adult snail. In his Systema Naturae , Carl von Linné described different age stages of the great fencing snail as different species. The synonymy of Strombus lucifer L. with Strombus gigas L. was already known in the first half of the 19th century .

Occurrence, distribution and way of life

The great fencing snail is native in the western Atlantic from Florida to northern Brazil and in the entire Caribbean , including the coasts of Mexico , the USA , the Bahamas and Bermuda .

The snail lives in seagrass meadows ( Thalassia spp., Especially Thalassia testudinum , Syringodium spp., Cymodocea spp.) And on sand at depths of about 0.3 m to 18 m. Young animals live in seagrass meadows in shallower waters than the adults and leave these youth quarters in mass migrations during the winter months when they are around 2 years old.

Compared to other snails, the great fencer can move quickly. To do this, she sinks the claw-shaped operculum into the substrate and throws the house forward with a jerky movement of the foot. In this way, the snail is able to climb vertical concrete walls without having to crawl on the sole of the foot. Since it leaves no trace of slime, it is also better protected from enemies.

The great fenugreek snail feeds on detritus and algae that grow on the seagrass, but also on the seagrass itself. Preferred food is the red algae of the species Batophora oerstedii and the genera Gracilaria and Hypnea .

The shell of the snail is sometimes inhabited commensally by cardinalfish ( Astrapogon stellatus ).

Enemies

Despite the considerable size that the great fencer snail can reach, and its rapid escape reactions , in which it leaves no trace of slime and thus escapes numerous enemies as an adult, it has many enemies, especially as a young animal. Their predators include various predatory snails , in particular the species Pleuroploca gigantea and Fasciolaria tulipa , which belong to the Fasciolariidae , as well as the spiny snail Phyllonotus pomum . Holes of moon snails and prickly snails have been found in empty shells of young animals . Other enemies are some decapods such as the blue crab ( Callinectes sapidus ), the pubic crab ( Calappa gallus ), the Caribbean lobster ( Panulirus argus ) and especially the giant hermit crab ( Petrochirus diogenes ). Crabs often break pieces of the shell from the edge of the mouth in order to get to the prey, but fencing snails are able to repair this damage after successfully escaping. Such repaired housings are found in particular from a housing length of 7.5 cm. Starfish are possible predators of young fencing snails, but in experiments specimens of the most common type of nosed pillow star ( Oreaster reticulatus ) in no case attacked young or old fencing snails and did not even trigger escape reactions when they came into direct contact. Among the fish , jackfish ( Trachinotus falcatus ) and spotted porcupine fish ( Diodon hystrix ) have been observed eating large fenced snails, as does the loggerhead turtle ( Caretta caretta ). The main enemy is man.

Use and hazard

The meat of the snail , called "Lambi" in the Dominican Republic , is eaten raw and cooked. The housings are sold to tourists. The Caribs and the indigenous peoples of Florida ( Tequesta ) made knives , axes and chisels from the edge of the casing . The species is endangered due to overfishing and is under species protection. It is listed in Appendix II of the Washington Convention on Species Protection and in Appendix B of the Federal Species Protection Ordinance . When entering or leaving the European Union, the housings of the fencing snail, popular as a souvenir, are subject to restrictions, so a maximum of three pieces of personal luggage may be carried without documents (as of 2013).

Pearl farming

Research into pearl cultivation has shown that the great fencer snail can also be induced to form pearls .

literature

Individual evidence

  1. ↑ World Register of Marine Species , Lobatus gigas (Linnaeus, 1758)
  2. ↑ World Register of Marine Species , Eustrombus gigas (Linnaeus, 1758)
  3. ^ A b Carolus Linnaeus : Systema Naturae. 10th ed., Lars Salvius: Stockholm 1758, p. 745. 434. Strombus Lucifer. 434. S. testae labro antice rotundato integro, ventre dupliciter striato, spira carinata: tuberculis superioribus minutis. Habitat ad Americam Australia. Differt a sequenti testa minus crassa, et imprimis spinis spirae minimis, nec magnis crassis pollicaribus ut in illa. Gigas power bus. 435. S. testa labro rotundato maximo, coronata ventre spiraque spinis conicis patentibus. Habitat in America. Testae color internus vividissimus.
  4. ↑ a b C. Brüggemann: The natural history in faithful illustrations and with a detailed description of the same. Eduard Eisenach publisher, Leipzig 1838. The molluscs. P. 77. The giant wing snail. Power bus Gigas L .; Strombus Lucifer L. is a young specimen.
  5. ^ Julia Ellen Rogers: The Shell Book. Doubleday, Page & Company, New York 1908, archive.org , p. 117 ff: The Queen Conch. Strombus gigas, Linn.
  6. ↑ Megan Davis (2005): Species Profile Queen Conch, Strombus gigas ( Memento of the original from March 24, 2012 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.ca.uky.edu archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.8 MB) . Southern Regional Aquaculture Center, SRAC Publication No. 7203
  7. ↑ Melany P. Puglisi: Strombus gigas (Queen Conch) . Smithsonian Marine Station at Fort Pierce, 2008.
  8. ↑ Queen Conch (Strombus gigas) . NOAA Fisheries Office of Protected Species.
  9. ^ R. Robertson: Observations on the spawn and veligers of conchs (Strombus) in the Bahamas. In: J. Molluscan Stud. 33 (4): 1959, 164-171, doi: 10.1093 / oxfordjournals.mollus.a064817 .
  10. ↑ Kevin McCarthy: A review of queen conch (Strombus gigas) life-history . (PDF; 114 kB). Sustainable Fisheries Division NOAA. SEDAR 14-DW-4, 2007.
  11. ↑ P. Medley: Monitoring and managing queen conch fisheries: A manual  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. @1@ 2Template: Dead Link / ftp.fao.org   . FAO Fisheries Technical Paper, p. 514. Food and Agriculture Organization of the United Nations (FAO), Rome 2008, ISBN 978-92-5-106031-5 .
  12. ↑ AW Stoner: Winter mass migration of juvenile queen conch Strombus gigas and their influence on the benthic environment . (PDF; 1.3 MB). Marine Ecology Progress Series 56, 1988, pp. 99-104.
  13. ↑ George Howard Parker: The leaping of the stromb (Strombus gigas Linn.). In: Journal of Experimental Zoology. 36 (2), 1922, pp. 205-209, doi: 10.1002 / jez.1400360204 .
  14. ↑ KO Hesse: Gliding and climbing behavior of the queen conch, Strombus gigas. In: Caribbean Journal of Science. 16, 1980, pp. 105-108.
  15. ↑ ES Iversen, EE Jory, SP Bannerot: Predation on queen conchs, Strombus gigas, in the Bahamas . In: Bulletin of Marine Science. 39 (1), 1986, pp. 61-75. online (PDF; 963 kB).
  16. ↑ EE Jory: An incident of predation on queen conch, Strombus gigas L. (Mollusca, Strombidae), by Atlantic permit, Trachinotus falcatus L. (Pisces, Carangidae). In: Journal of Fish Biology. (The Fisheries Society of the British Isles) 28 (2), 2006, pp. 129-131, doi: 10.1111 / j.1095-8649.1986.tb05149.x .
  17. ^ Taxon Information. Federal Agency for Nature Conservation, accessed on October 12, 2009 .
  18. ↑ Species protection, to what extent am I as a traveler affected by this? Federal Ministry of Finance, accessed on July 3, 2013 .
  19. ^ Report from the field of science. Spiegel Online, accessed November 4, 2009 .

Web links

Commons : Lobatus gigas  - collection of images