''Ophiura albida'' is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
brittle star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...
in the
order Ophiurida
The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars.
Characteristics
Ophiurida have bursae for respiration and excretion, and dorsal and ventral arm shields are present a ...
. It is typically found on the seabed in the north eastern Atlantic Ocean and in the Mediterranean Sea and is sometimes known as the serpent's table brittle star.
Description
''Ophiura albida'' has a central disc reaching a diameter of about and five arms up to long. The disc is flattened and the upper surface is covered in small plates. These are mostly brick red but the plates at the edge of the disc close to where the arms are attached are white. The arms are slender and fragile, segmented and gradually tapering. The plates on the upper and lower sides have convex edges. Each segment has three short spines which lie flat on the surface and there are small pores between the plates. This latter fact helps to distinguish this species from the otherwise very similar ''
Ophiura ophiura
''Ophiura ophiura'' or the serpent star is a species of brittle star in the order Ophiurida. It is typically found on coastal seabeds around northwestern Europe.
Description
''Ophiura ophiura'' has a circular central disc up to 35 mm (1.5 ...
''. The underside of the disc is a pale colour and has a central mouth with five large plates modified as jaws and fringed with teeth.
Distribution and habitat
''Ophiura albida'' is found at depths down to about , or according to one authority. Its range extends from Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
to the Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
and the Azores
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, anthem= ( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
. It occurs on the seabed on soft substrates including coarse sand, fine sand, gravel and muddy sand.[ It is common round the coasts of the ]British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...
and has occurred at densities as great as 900 per .[
]
Biology
''Ophiura albida'' is a predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
and scavenger and feeds on such small invertebrates as polychaete worms, crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s and bivalve molluscs
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
.[ In the ]Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain.
The sea stretches from 53°N to 66°N latitude and ...
it is the favourite food of the starfish '' Luidia sarsi'' and is chosen in preference to other brittle stars. In the Irish Sea it is eaten along with the common brittle star (''Ophiothrix fragilis
''Ophiothrix fragilis'' is a species of brittle star in the order Ophiurida. It is found around the coasts of western Europe and is known in Britain as the common brittle star. It is also found along the coast of South Africa where it is known ...
'') by the fast-moving seven armed starfish ('' Luidia ciliaris'').plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...
ic. It is a fast-growing brittle star and is not thought to live for more than three years.[
]
References
{{Taxonbar, from=Q1602788
Ophiuridae
Animals described in 1839