Compass jellyfish
| Compass jellyfish | ||||||||||||
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Compass jellyfish ( Chrysaora hysoscella ) in the Genoa aquarium |
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| Scientific name | ||||||||||||
| Chrysaora hysoscella | ||||||||||||
| ( Linnaeus , 1766) |
The compass jellyfish ( Chrysaora hysoscella ) is a species of umbrella jellyfish found in the Atlantic, Mediterranean , North Sea and Kattegat .
features
It has an umbrella diameter of around 25 to 30 cm (maximum 35 cm) and is easy to recognize thanks to the characteristic drawing with radially arranged yellow-brown, orange, red or dark-brown bands reminiscent of a compass rose . The relatively flat screen is otherwise colorless, whitish, yellowish-white, orange or brown. The edge of the umbrella is lobed and covered with 24 short, strong tentacles that are located in the spaces between the lobes. The equally large 32 to 48 lobes are semicircular. Around the mouth opening there are further tentacles with a V-shaped cross-section, the length of which can reach five times the diameter of the umbrella. The ends of the tentacles, which are also often missing, are wound up in a spiral and have nettle cells that cause skin irritation and irritation in humans, including circulatory problems and the like, due to their nettle toxin . Ä. Count, can cause. The tentacles are white, yellowish, orange and rarely brown. The gastric space is divided into 16 bag-like sections.
Way of life
Compass jellyfish usually move a few meters below the surface of the water. Young medusas are first found on the coasts of the British Isles in May, larger animals from mid-June to September. On the Dutch coast they occur mainly from mid-August to mid-October. The medusas are hermaphroditic , develop only male genital organs at first, then have male and female genital organs at the same time and finally only female ones. The eggs are fertilized in the “mother animal”, and the planula larvae that develop from them are then released into the open water. Self-fertilization is possible in the hermaphroditic intermediate phase. The planula larvae settle on the seabed and form an asexual " scyphopolyp ", which asexually forms tiny " ephyral larvae ". These live in plankton and after a while become sexually mature jellyfish.
floating compass jellyfish: the yellow-brown bands and the lapping of the screen are easy to see.
swimming compass jellyfish with tentacles that can cause burns in humans due to their nettle poison.
literature
- Matthias Bergbauer, Bernd Humberg: What lives in the Mediterranean? 1999, Franckh-Kosmos Verlag, ISBN 3-440-07733-0
Web links
- Chrysaora hysoscella on the Marine Species Identification Portal.
- Compass jellyfish. Article on the Wadden Sea Protection Station website, accessed on May 9, 2013.