Nematode worm
| Nematode worm | ||||||||||||
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Nematode worm |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cirratulus cirratus | ||||||||||||
| OV Müller , 1776 |
The cluster of thread worm or Nordic tendrils worm ( Cirratulus cirratus ) is a sessile, as filter feeders living polychaete (Polychaeta), when buried in mud or sand in the Atlantic Ocean and the North Sea can be found.
features
The nematode worm has a cylindrical body, which is up to 30 cm long and has about 150 segments . There are 4 to 8 large black eyes on the sides of the obtuse cone-shaped prostomium . The following 3 segments, which are very similar to one another, have straight edges. Two groups of 2 to 24 palps sit on the front edge of the first bristle-bearing segment. The long, thread-like gills , which are about the size of the palps, sit on each segment, starting with the first bristle-bearing segment and almost to the end of the tail. There are capillary-shaped bristles on all the bristle-bearing segments , but short, strong bristles are also located ventrally from the 10th to 12th and dorsally from the 20th to 23rd segment. The body is orange or pink to brownish red, the gills and palps red to yellow.
distribution and habitat
The tufted worm is distributed throughout the Atlantic Ocean , in the North Sea , the Skagerrak and Kattegat to the Öresund . The polychaet lives in the deeper bank zones in mud or muddy sand or between rocks, usually in groups of up to 200 individuals.
Development cycle
The nematode worm is sexually separate. The females ready to mate take on a light yellow color due to the numerous egg cells in their coelom , the males a white color due to the sperm . Both sexes release their gametes into the open sea water, where the yolk- rich eggs anchored in a gelatinous mass on a solid substrate are fertilized by the sperm. After six days, free-swimming post-trochophora larvae hatch, feed on supplies of yolk and after about 24 days sink down and metamorphose into crawling worms in order to dig into the sediment and live sessile as filter feeders . A female can lay eggs every 1 to 2 years and will do so 2 to 3 times in her life. There is no fixed mating season in the year.
nutrition
The cluster of thread worm feeds as filter feeders of detritus and microscopic algae , which he captures with its tentacles directly from the water flow or fluidized soil particles and transported by ciliary activity to the mouth.
literature
- Gesa Hartmann-Schröder (1996): Annelida, Borstenwürmer, Polychaeta. Tierwelt Deutschlands 58, pp. 1–648, here p. 358, Cirratulus cirratus OF Müller, 1776.
- John D. Fish, Susan Fish: A Student's Guide to the Seashore . Cambridge University Press, Cambridge 2011. 540 pages. Cirratulus cirratus OF Müller , p. 163.
- PJW Olive (1970): Reproduction of a Northumberland population of the polychaete Cirratulus cirratus. Marine Biology 5 (3), pp. 259-273.
- PE Gibbs (1971): A Comparative study of Reproductive Cycles in Four polychaete Species belonging to the Family Cirratulidae. Journal of the Marine Biological Association of the United Kingdom 51 (4), pp. 745-769.
Web links
- MJ de Kluijver et al .: Cirratulus cirratus (OF Müller, 1776). Macrobenthos of the North Sea - Polychaeta, Marine Species Identification Portal
- KJ Neal, S. Ballerstedt: Cirratulus cirratus (OF Müller, 1776). In: H. Tyler-Walters, K. Hiscock (Eds.): Marine Life Information Network, Biology and Sensitivity Key Information Reviews. Marine Biological Association of the United Kingdom, Plymouth 2006.