Glaucus atlanticus
| Glaucus atlanticus | ||||||||||||
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Glaucus atlanticus |
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| Forster , 1777 | ||||||||||||
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| Glaucus atlanticus | ||||||||||||
| Forster, 1777 |
Glaucus atlanticus (German: Blaue Ozeanschnecke, Blauer Drachen or Seeschwalbe) is a thread snail from the family Glaucidae in the suborder of the nudibranch (Nudibranchia), whichlives pelagically on the sea surface andeats cnidarians .
features
Your body has laterally limb-like protuberances that are used for buoyancy. At the end of these outgrowths there are again tufted processes called cerata , which lead into the outgrowths of the midgut gland . The snail becomes 3 to 5 cm long. The back of the animal is colored silvery-gray to protect itself from predators.
nutrition
The snails feed on cnidarians such as sailing and state jellyfish (genera Velella , Porpita and Physalia ). The prey's nettle cells are stored in the cerata and serve as protection for the snails from eating. It is unknown how the nettle pods are kept from exploding while the jellyfish's poisonous cells are eaten. This ingestion of food makes the Glaucus atlanticus itself poisonous, which protects it from predators. Depending on the amount of substance stored, it can be even more dangerous than its prey.
Occurrence and way of life
The marine nudibranch Glaucus atlanticus lives pelagically in warm and temperate seas. Regions where this nudibranch can be found are the east and south coasts of South Africa, European waters, the east coast of Australia, and Mozambique. It floats, belly upwards, with the help of gas bubbles on the surface of the water or attaches itself to floating seaweed; conceptually it belongs to the Pleuston .
The limb-like protuberances, the cerata, give the Glaucus a lift . An animal has up to 84 cerata. Glaucus atalanticus can also swallow air bubbles, stow them in a sack in their stomach and thereby gain additional buoyancy.
Life cycle
Like other thread snails, Glaucus atlanticus is a hermaphrodite . The penis is provided with a chitin spike. The female genital opening is on the right of the abdomen. The eggs, which are 60 to 75 µm wide and 75 to 97 µm long, are attached to the remains of meals in straight strings up to 17.5 mm long during sexual intercourse. At 19 ° C, the furrow begins after a few hours. After 48 to 60 hours a trochophora forms and after three days a veliger with a shell, which leaves the egg cord. 11 days after hatching, the first coils of the shell are formed.
With the metamorphosis , the shell is lost and a shell-less thread snail is created.
Systematics
Glaucus atlanticus Forster, 1777 forms together with the smaller sister species Glaucus marginatus (Bergh, 1860), original name Glaucilla marginata Bergh, 1860, the family Glaucidae . Traditionally, the two genera Glaucus Forster, 1777 and Glaucilla Bergh, 1860 were monotypical , i.e. that is, they each contained only one of the two sister species. Ángel Valdés and Orso Angulo Campillo placed both species in the genus Glaucus in 2004 .
literature
- Carol M. Lalli and Ronald W. Gilmer: Pelagic Snails: The Biology of Holoplanktonic Gastropod Mollusks. 259 S., Stanford, Calif., Stanford Univ. Pr., 1989. Glaucidae : pp. 224-228. ISBN 0-8047-1490-8
Web links
- Marine Species Identification Portal: Glaucus atlanticus
- WB Rudman (1998): Glaucus atlanticus Forster, 1777. Sea Slug Forum, Australian Museum, Sydney
Individual evidence
- ↑ Glaucus atlanticus - the blue ocean snail . In: world's largest collection of animal stories . ( tiergeschichten.de [accessed on November 17, 2018]).
- ↑ Ángel Valdés and Orso Angulo Campillo: Systematics of pelagic aeolid nudibranchs of the family Glaucidae (Mollusca, Gastropoda). Bulletin of Marine Science, 75 (3): 381-389, Coral Gables, Fla. 2004 ISSN 0007-4977