Sea sandworm
| Sea sandworm | ||||||||||||
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Thalassema thalassemum , Pointe du Conguel, Quiberon, France |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Thalassema thalassemum | ||||||||||||
| ( Pallas , 1774) |
The sea sandworm ( Thalassema thalassemum ) is a representative of the hedgehog worms (Echiura) from the Thalassematidae family, which is distributed in the Atlantic Ocean .
features
Thalassema thalassemum has a sack-shaped, tapered trunk with a length of about 2 to 7 cm. At the front end there is a long, rounded or pointed proboscis that can be extended up to a length of about 10 to 20 cm with a conspicuous belly-side eyelash groove, at the base of which is the mouth on the trunk. The surface of the trunk is covered with many papillae arranged in rings around the body, especially in the posterior part of the body, where they increase in number. There are two ventral bristles at the front end, while they are missing at the rear end. The animal can be of various colors, such as blue, gray, yellow, pink, or orange, with a white line running down the center of the surface on the abdomen. The Proboscis, on the other hand, is peach to cream-colored. The sea sandworm has two pairs of nephridia . It can contract to a length of about 2 to 3 cm.
distribution
Thalassema thalassemum is widespread in the Atlantic Ocean from the Mediterranean Sea to the southwest coast of the British Isles, exceptionally also to the southwest coast of Scotland, where it lives in the intertidal zone and below in rock crevices and between stones, below the intertidal zone but also in sand and mud.
Habitat and way of life
Thalassema thalassemum feeds on detritus and microorganisms that are grazed from the substrate with the proboscis. It is mainly nocturnal.
Life cycle
In Thalassema thalassemum, males and females are the same size and come together to mate in summer. The gametes are released via the nephridia, so that fertilization takes place in the open sea water. The floating Trochophora - larvae live for a while as zooplankton before they sink down and ground-dwelling worms metamorphose .
Initial description
The sea sandworm was described by Peter Simon Pallas in 1774 under the name Lumbricus thalassemum and thus placed in a genus with earthworms . In 1801 Jean-Baptiste de Lamarck established the genus Thalassema with the type species Thalassema rupium , which is a synonym of the species name Thalassema thalassemum , which is valid today . Both parts of the name are derived from the Greek words θάλασσα "sea" and σῆμα "sign".
literature
- JD Fish, S. Fish: A Student's Guide to the Seashore. Cambridge University Press, 2011. p. 380.
- Peter J. Hayward, John S. Ryland: Handbook of the Marine Fauna of North-West Europe. Oxford University Press, 2017. p. 276.
Web links
- Lexicon of Biology : Thalassema
- Saskiya Richards: A spoon worm (Thalassema thalassema) MarLIN, The Marine Life Information Network, 2009.