Erenna

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Erenna
prepared specimen in the Peabody Museum of Natural History

prepared specimen in the Peabody Museum of Natural History

Systematics
Trunk : Cnidarians (Cnidaria)
Class : Hydrozoa (Hydrozoa)
Order : State jellyfish (Siphonophorae)
Subordination : Physonectae
Family : Erennidae
Genre : Erenna
Scientific name
Erenna
Bedot , 1904

Erenna is a genus of the state jellyfish that occurs in the deep sea at depths between 1600 and 2000 m. She was formerly the family Agalmidae attributed, however, a new family of PR Pugh in 2001 Erennidae assigned.

morphology

Like all state jellyfish, the species of the genus Erenna consist of many highly specialized and diverse individual animals. The tentacles have a multitude of side arms, so-called tentilla or tentils . Each of these consists of a large band of up to 3000 stinging cells attached to a central stem. The stem continues in a white dotted, pear-shaped body, the ocelli . If it is torn in calcium chloride solution, these points begin to luminesce . It is therefore a luminous organ that is filled with photoproteins regulated by calcium ions. At least one species ( Erenna sp. Nov. ) Can produce red light in this way. In contrast to photocells from other cnidarians , they do not start to glow immediately after stimulation.

behavior

The animals live widely scattered in the deep sea . With their luminous organs they generate rhythmically pulsing light and thus lure fish, which they then kill and eat with their nettle poison. They probably also feed on small crabs .

At least with regard to the red luminescent species, however, it is noteworthy that so far only very few species are known that can recognize the color red at such a depth and thus come into question as food for Erenna. It is therefore not yet clear how the limited food supply is sufficient for Erenna to survive.

Systematics

Until 2005 there were three described species in the genus Erenna :

  • Erenna richardi , Bedot, 1904 ( Syn . : Erenna bedoti , Lens & van Riemsdijk, 1908)
  • Erenna cornuta , Pugh, 2001
  • Erenna laciniata , Pugh, 2001

In 2005 US researchers caught some specimens of a new species of the genus Erenna ( Erenna sp. Nov. ) From a depth of 1,600 to 2,600 m, which had not yet been described before. This species can emit red light.

literature

  • PR Pugh: A review of the genus Erenna Bedot, 1904 (Siphonophora, Physonectae) in Bulletin of the Natural History Museum: Zoology Series , Vol. 67, (2), pp. 169-182.
  • Steven HD Haddock et al .: Bioluminescent and Red-Fluorescent Lures in a Deep-Sea Siphonophore. in Science , Vol. 309, July 8, 2005, page 263. doi : 10.1126 / science.1110441 pdf

Individual evidence

  1. ↑ Science : Bioluminescent and Red-Fluorescent Lures in a Deep-Sea Siphonophore (Abstract) , published July 8, 2005, loaded October 5, 2017

Web links