Sea anemones

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Sea anemones
Fish-eating sea dahlia (Urticina piscivora)

Fish-eating sea dahlia ( Urticina piscivora )

without rank: Multicellular animals (Metazoa)
without rank: Tissue animals (Eumetazoa)
Trunk : Cnidarians (Cnidaria)
Class : Flower animals (anthozoa)
Subclass : Hexacorallia
Order : Sea anemones
Scientific name
Hertwig , 1882

Sea anemones (Actiniaria), also called water lilies , sea ​​carnations or actinias , are a species-rich and generic order of the Hexacorallia within the flower animals (Anthozoa). They are exclusively living in the sea, always solitary , mostly relatively large animals that occur from shallow water to abyssal depths. About 1200 species are currently known.


Sea anemones have no skeleton and live solitary , i. That is, they do not form colonies in contrast to most other representatives of the flower animals. You are semi-sessile ; they can move by slowly crawling on their footplate, which they normally use to cling to hard ground or dig into sand and rubble. Your body is muscular. The size can range from one to 150 centimeters, depending on the species. Their tentacles are simple and usually not branched, and often translucent. Some species have nettle threads , here called acontia , which are ejected through the mouth or through pores in the scapus, so-called cinclidia. Various forms of modes of reproduction are known. Separate, but also hermaphroditic species exist. There is even a cross-division or constriction of the foot sections.

Geographical occurrence, distribution and way of life

There are over 1200 species in all seas from shallow water to 10,000 m depth. About 60 species are found in European waters. Many adult actinia eat fish , crabs and snails , others only plankton .


Partner shrimp between anemone tentacles

Some species form symbioses with other animals. So find z. B. anemonefish , the anemone goby , spider crabs or partner shrimp between the tentacles protection from enemies, or hermit crabs attach the parasite rose to the snail shells they inhabit ( ectosymbiosis ).


A current system divides the sea anemones on the basis of a phylogenetic investigation, in which two genes from mitochondrial DNA and three genes from the cell nucleus of 123 different sea anemone species were compared with one another, into two sub-orders and five superfamilies.

Edwardsiella andrillae - species from Antarctica from the bottom of the ice shelf
Nematostella vectensis - model organism with a fully sequenced genome
Glass rose ( Aiptasia sp.)
Sea carnation ( Metridium senile )
Fly trap sea anemone
Flytrap sea anemone on a coral hill off Ireland in 780 meters water depth

Individual evidence

  1. ^ Bernhard Werner: Tribe Cnidaria . In: Textbook of Special Zoology. Volume I: Invertebrates Part 2: Cnidaria, Ctenophora, Mesozoa, Plathelminthes, Nemertini, Entoprocta, Nemathelminthes, Priapulida. 4th completely revised edition, pp. 11–305, Gustav Fischer Verlag, Stuttgart 1984 ISBN 3-437-20261-8
  2. Estefania Rodriguez, Marcos S. Barbeitos, Mercer R. Brugler, Louise M. Crowley, Alejandro Grajales, Luciana Gusmao, Verena Häussermann, Abigail Reft, Marymegan Daly: Hidden among Sea Anemones: The First Comprehensive Phylogenetic Reconstruction of the Order Actiniaria (Cnidaria , Anthozoa, Hexacorallia) Reveals a Novel Group of Hexacorals. PLOS ONE , May 2014, Volume 9, Issue 5, e96998, DOI: 10.1371 / journal.pone.0096998 .


  • Harry Erhardt, Horst Moosleitner: Sea water atlas. Volume 1 Mergus-Verlag, Melle 2006, ISBN 3-88244-020-1 .

Web links

Commons : Sea Anemones  - Collection of images, videos and audio files