Brown ringworm
| Brown ringworm | ||||||||||||
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Brown ringworm ( Nereis pelagica ) |
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| Scientific name | ||||||||||||
| Nereis pelagica | ||||||||||||
| Linnaeus , 1758 |
The brown ragworm ( Nereis pelagica ) is up to 15 cm high cosmopolitan marine annelid from the genus Nereis within the polychaete - family of Nereididae .
features
The brown ringworm has a long body that narrows towards the rear and a surface that is convex on the rear. It becomes up to 15 cm long and then has about 100 segments . His prostomium has a pair of antennae without antenna support and a pair of two-part palps that are longer than the antennae, as well as 2 pairs of eyes arranged in a trapezoid. On the bristle-free peristomium there are four pairs of tentacles - cirrus on short cirrus carriers, the dorsal tentacle cirrus being longer than the ventral and the second dorsal tentacle cirrus extending to the fifth bristle-bearing segment. The pharynx has a pair of toothed jaws. The mouth and maxillary rings have conical paragnaths. The articulated bristles are long and thin.
Each segment has parapodia , which are single-branched with 3 lobes in the first two segments, whereas in the other segments they are bifurcated with 4 lobes, a dorsal lobe of the notopodium , an acicula lobe of the notopodium, an acicula lobe of the neuropodium and a ventral lobe of the neuropodium.
The lobes of the notopodium are about the same length, while the ventral lobe of the neuropodium is slightly shorter and the acicula lobe of the neuropodium is the shortest. The dorsal lobe and the acicula lobe of the notopodium, like the ventral lobe of the neuropodium, are broadly rounded in the anterior segments, with both lobes of the notopodium becoming somewhat longer in the posterior segments. The acicula lobe of the neuropodium has an only poorly developed posterior bristle lobe. The dorsal cirrus is longer than the lobes of the parapodia, the ventral cirrus is shorter or about as long as the ventral lobe of the neuropodium. The pygidium (rear end) of the brown ringworm has two cirrus cirrus.
The color of the body is yellowish, thorough, golden brown, reddish brown, olive green or violet, with the blood vessels appearing clearly red due to the blood pigment hemoglobin dissolved in the blood plasma .
Distribution, habitat and way of life
Nereis pelagica is cosmopolitan in all oceans on both hemispheres, including in the Atlantic Ocean including the North Sea and the western Baltic Sea , in the Mediterranean and in the Pacific Ocean .
The brown ringworm lives mainly in the intertidal zone, but occasionally also below it to a depth of about 120 m, where the externally similar Nereis zonata usually takes its place. It lives in mucus tubes on the underside of stones and rocks or under large algae .
Nereis pelagica is an omnivore that feeds primarily on bacteria that live on the substrate.
Life cycle
The green ringworm can live up to 3 years. It is separate sexes with females and males of roughly the same size, who come together in large numbers free-swimming as sexually mature female and male epitokes with leaf-like enlarged parapodia and die after the gametes are released into the seawater. On the northeast coast of England, the mating season extends from December to April. The fertilization takes place in the open sea water. After fertilization, larvae develop from the eggs, which, depending on the environmental conditions, live benthically on the sea floor or swim freely as zooplankton and after a few days metamorphose into crawling worms .
Initial description
Nereis pelagica is the type species of the genus Nereis and was described by Carl von Linné as one of the first multi-bristles as early as 1758 .
literature
- Volker Storch, Ulrich Welsch: Kükenthal zoological internship. 26th edition, Spektrum Akademischer Verlag, 2009 ISBN 3-8274-1998-0
- JD Fish, S. Fish: A Student's Guide to the Seashore. Cambridge University Press, Cambridge 2011. p. 152.
- PJ Hayward, JS Ryland: Handbook of the Marine Fauna of North-West Europe. Oxford University Press, Oxford 1995. p. 210.
- Douglas P. Wilson (1932): The Development of Nereis pelagica Linnaeus. Journal of the Marine Biological Association of the United Kingdom 18, pp. 203-217.
Web links
- Underwater world Baltic Sea
- MJ de Kluijver et al .: Nereis pelagica Linnaeus, 1758. Macrobenthos of the North Sea - Polychaeta, Marine Species Identification Portal