Common pearl boat
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Nautilus pompilius , Pairi Daiza Zoo, Brugelette , Belgium |
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| Scientific name | ||||||||||||
| Nautilus pompilius | ||||||||||||
| Linnaeus , 1758 |
The common pearl boat , also ship boat , ( Nautilus pompilius ) is a cephalopod from the family of pearl boats , which is common in the Pacific Ocean . It is the most common species in this family.
features
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The housing of Nautilus pompilius is thin-walled and can reach a diameter of 30 cm. The smooth surface has a white base color on which - as with other Nautilus species - brown and white horizontal stripes alternate. The navel of the housing is similar to Nautilus belauensis by a callus sealed.
The interior of the bowl, wound as a logarithmic spiral , the phragmocone , consists of up to 30, sometimes more than 38 gas-filled chambers, which are separated from each other by partition walls (septa). In the newly hatched animal there are only four chambers. The animal lives in the outermost, youngest chamber, the living chamber, from which further chambers of the phragmocone are formed by the formation of new septa. The gas mixture, which contains around 0.30 bar nitrogen, 0.29 bar oxygen and 0.0005 bar argon, passes through an extension of the animal, the siphunculus ( sipho ), into the chambers, which are partially still filled with water. The siphunculus is permeated with blood vessels through which gases can be released or absorbed in order to regulate the buoyancy of the animal in the water. The shell can withstand a pressure of around 60 bar, which corresponds to a depth of 600 meters.
The animal can withdraw into the shell and close it with a sturdy hood-like cover.
Up to 90 tentacles are coated with a sticky secretion to hold prey.
The horny beak, the lower half of which is stronger than the upper half, has calcified tips. The radula is 13 parts in each row with rachis teeth, two posterior teeth, two marginal teeth and two marginal plates.
Like other nautical boats, Nautilus pompilius has eyes with holes .
The pearl boat, which can float in the water with the help of its gas-filled phragmocone , moves slowly, bobbing about, not going faster than two centimeters per second.
Reproductive cycle
The male visits the female with the help of the sense of smell. During copulation, four modified tentacles of the male serve as the copulation organ, with the help of which the spermatophores , spermatozoids wrapped in jelly, are transferred to the female. The jelly dissolves in the fallopian tube and the sperm fertilizes the egg cells. The very yolk-rich eggs are laid in shallower water. Only after about 12 months do the young animals, which are already 3 cm long, hatch. Nautilus pompilius can live around 20 years, so lives significantly longer than octopuses and squids .
distribution
The common pearl boat lives in tropical waters of the western Pacific and the eastern Indian Ocean . It prefers the slopes of coral reefs , where it occurs at depths of around 400 meters to 650 meters, and up to 100 meters at night.
The subspecies Nautilus pompilius pompilius , which reaches shell sizes of over 30 cm, lives from the Andaman Sea via Indonesia to Fiji and from southern Japan to the Great Barrier Reef of Australia . The other subspecies Nautilus pompilius suluensis , which only grows up to 16 cm, is restricted to the Sulu Sea in the southwestern Philippines .
Way of life
Nautilus pompilius is nocturnal and feeds on small crabs , as well as carrion and occasionally small fish.
Use and endangerment
Finds from East Timor show that around 40,000 years ago people made jewelry out of pearl boat shells. Even today, the bowl of Nautilus pompilius is marketed as a souvenir and collector's item . In addition, like other cephalopods, pearl boats are fished for their meat. Although it is by far the most common type of pearl boat, it is therefore also endangered. Due to the slow growth rate, losses can be difficult to compensate for.
In the Philippines, pearl boats are caught with traps made of bamboo and rattan. Chicken meat is usually used as bait, but also toads, fish and pork meat. Is caught Nautilus pompilius m at depths of 150 to 200 with networks up to 300 m depth.
Systematics
The name Nautilus pompilius goes back to the Systema naturae of Carl von Linné , whereby the Greek generic name ναυτίλος means "sailor". Nautilus pompilius is one of five recent species of the genus Nautilus or seven species of the family Nautilidae. There are two subspecies, Nautilus pompilius pompilius and Nautilus pompilius suluensis .
literature
- Lawrence Edmonds Griffin: The anatomy of Nautilus pompilius . Memoirs of the National Academy of Sciences, Vol. VIII. United States Government Printing Office , Washington, DC 1900.
- Takenori Sasaki, Shuichi Shigeno, Kazushige Tanabe: Anatomy of living Nautilus. Reevaluation of primitiveness and comparison with Coleoidea (PDF; 1.3 MB) . In: Kazushige Tanabe, Y. Shigeta, T. Sasaki, H. Hirano (Eds.): Cephalopods - Present and Past . Tokai University Press, Tokyo 2010, pp. 35-66.
Web links
- The pearl boat ( Nautilus pompilius ) on weichtiere.at
- Aquarium of the Pacific (Long Beach): Chambered Nautilus - Nautilus pompilius
Individual evidence
- ↑ Ulrich Sommer : Biological Oceanography . Springer Verlag, Berlin Heidelberg 2005, p. 54.
- ↑ a b Michelle C. Langley, Sue O'Connor, Elena Piotto: 42,000-year-old worked and pigment-stained Nautilus shell from Jerimalai (Timor-Leste): Evidence for an early coastal adaptation in ISEA
- ^ William Broad: Loving the Chambered Nautilus to Death . In: The New York Times , October 24, 2011. Archived from the original on October 24, 2011.