Common brittle star
| Common brittle star | ||||||||||||
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Common brittle star, found at Neeltje Jans, Nederlande |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ophiura ophiura | ||||||||||||
| ( Linnaeus , 1758) |
The Common brittle star or large brittle star ( Ophiura Ophiura ) is a brittle star from the genus Ophiura in the family of Ophiuridae .
features
The body disc reaches a diameter of up to 35 mm, the relatively short arms 3.5 times the body disc diameter. The color varies from gray-brown to sand-orange, the underside is lighter than the top. The body scales are granular, the primary plates clear, especially the central primary plate. The radial shields are large (about half the body disk radius). There are two layers of arm combs over each arm, the outer one consists of about 30 fine papillae. The mouth shields are large and reach about two thirds of the distance from the edge of the disc to the adoral plate. There is a single vertical row of teeth on the top of the jaw, and there are four to six oral papillae on each side of the jaw.
The dorsal arm plates in the notch above the arm are rectangular or triangular. The free dorsal arm plates in the proximal section of the arms are 4 to 5 times as wide as they are long with a straight or only slightly concave outer edge and touch each other along their entire length. The ventral arm plates are twice as wide as long with a convex outer edge; they are separated from each other by a pair of pore-shaped depressions in the center line of the arm. Three pairs of arm spikes are flat against the arms. The openings for the suction feet each have 3 to 4 tentacle scales in the proximal section of the arm, further outside only 2 and at the very outside only one.
distribution
Ophiura ophiura occurs on all coasts of the North Sea . In addition, the distribution area includes the northeast Atlantic from Norway to Madeira and the Mediterranean .
Habitat and way of life
Ophiura ophiura lives on a variety of soft substrates , usually sublittoral , from low water to depths of at least 200 m. Sometimes he digs himself in sand or mud.
Development cycle
Ophiura ophiura is separate sex. To mate, both males and females release their gametes into the open sea, where fertilization takes place. As with most brittle stars, the zygotes develop into free-swimming Ophiopluteus larvae that live as zooplankton until they sink down and metamorphose into small brittle stars .
nutrition
Ophiura Ophiura feeds as omnivores both detritusreichem mud as well as various small animals, including particularly of freshly metamorphosed , very small animals such as juvenile brittle stars and other young echinoderms , clams , snails , Vielborstern and crabs in very large numbers. Based on this, Howard M. Feder estimates the destructive potential of Ophiura ophiura and omnivores with similar behavior as higher than that of specialized predators such as moon snails .
Individual evidence
- ↑ Wadden Sea Protection Station: Online Animal of the Month December 2016
- ↑ a b Theodor CH Cole: Dictionary of the invertebrates. , P. 560.
- ↑ a b c d e M. J. de Kluijver, SS Ingalsuo: Ophiura ophiura. Macrobenthos of the North Sea - Echinodermata, Marine Species Identification Portal.
- ^ PJ Hayward, JS Ryland: Handbook of the Marine Fauna of North-West Europe. Oxford University Press, 1990, ISBN 978-0198540557 , p. 673.
- ↑ John D. Fish, Susan Fish: A Student's Guide to the Seashore . Cambridge University Press, Cambridge 2011. 540 pages. Ophiura ophiura (Linnaeus) , p. 448, p. 408.
- ^ Gunnar Thorson (1966): Some factors influencing the recruitment and establishment of marine benthic communities. Netherlands Journal of Sea Research 8 (2), pp. 267-293, here p. 282.
- ^ Howard M. Feder (1981): Aspects of the feeding biology of the brittle star Ophiura texturata. Ophelia 20 (2), pp. 215-235.