Nematostella vectensis
| Nematostella vectensis | ||||||||||||
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Nematostella vectensis |
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| Scientific name | ||||||||||||
| Nematostella vectensis | ||||||||||||
| Stephenson , 1935 |
Nematostella vectensis is a sea anemone thatoccurs in the North Atlantic and in recent years has become a model organism for studying the development of the complexity of animal blueprints .
features
Nematostella vectensis is a small, elongated sea anemone with 12 to 20, usually 16 tentacles in two circles around the mouth opening . The outer circle is longer and usually points outwards and downwards, while the tentacles of the inner circle are stretched upwards. All tentacles are slightly thickened at the base, but then run long and thin to a slightly enlarged tip. They are colorless with pale tips and irregularly spaced white stripes. The mouth opening sits on a slightly conical elevation.
The trunk is externally whitish to light gray, the translucent mesenteries are, depending on the food, pale pink, greenish, brown or blackish. In the stretched state, the trunk is about four to six times as long as it is wide, smooth and translucent and usually reaches a length of 10 to 15 millimeters in the open air. However, especially in the laboratory, the animals can get significantly larger up to six centimeters in length. When contracted, the trunk is only about twice as long as it is wide and appears wrinkled and opaque. Externally, the fuselage is divided into three sections, which, however, do not stand out from each other very clearly. The capitulum is just a short translucent section. The scapus has a ring of cream-colored markings just below the tentacles, followed by a translucent band and then another series of cream-colored spots that run down the trunk and fade in the process. The physa, when extended, is a translucent vesicle through which the mesenteries are clearly visible. It can be partially drawn in, but not completely inversed into the scapus.
Occurrence
The species is known from the south-east coasts of Great Britain and the Atlantic and Pacific coasts of North America , where it occurs in individual populations in suitable locations. Due to the scattered distribution in partially threatened by pollution habitats it is in the Red List of the International Union for Conservation of Nature and Natural Resources (IUCN) as endangered ( Vulnerable listings).
Way of life
Nematostella vectensis colonizes fine-grained mud surfaces on the edges of tides in salt marshes and brackish pools . Usually they are buried with the tentacles up to the tip of the trunk. But occasionally they are also open or to seagrasses attached. They tolerate relatively large fluctuations in salinity and temperature.
literature
- Thomas Alan Stephenson: The British Sea Anemones. Volume II . The Royal Society, London 1937, p. 44-52 .
- Susan M. Wells, Robert M. Pyle, N. Mark Collins (Eds.): The IUCN Invertebrate Red Data Book . IUCN, Gland 1983, ISBN 2-88032-602-8 , pp. 43-46 .
Individual evidence
- ^ Sol Felty Light, James T. Carlton: The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon . 4th edition. University of California Press, 2007, ISBN 978-0-520-23939-5 , pp. 180 .
- ^ Thomas Alan Stephenson: The British Sea Anemones. Volume II . The Royal Society, London 1937, p. 44-52 .
- ^ Nematostella vectensis in the IUCN Red List of Threatened Species .
- ↑ a b Susan M. Wells, Robert M. Pyle, N. Mark Collins (Eds.): The IUCN Invertebrate Red Data Book . IUCN, Gland 1983, ISBN 2-88032-602-8 , pp. 43-46 .