Ophiocoma echinata is eaten by some fish.
One of the larger brittle stars, Ophiocoma echinata can measure up to 32 mm in disk diameter and 150 mm in arm length. The spiny brittle star shares the characteristic body plan of echinoderms, with 5 arms that are well defined from the central disk. The aboral, or top, side of the star is dark brown and sometimes mottled with lighter hues. The arms are usually banded in shades of brown and the oral, or bottom, surface is white in color. The central disk is granular and exhibits a scalloped border. The mouth is located on the oral surface and consists of 5 triangular jaws, each with a central column of teeth. The arms extend out from the muscular jaws and are covered by 4 rows of shields, or calcareous plates. Each arm joint has a vertical row of 4 spines on either side. The length of the spines decease towards the tip of the arm and the spine closest to the mouth is club-shaped. Unlike the asteroids (sea stars), brittle stars have no umbulacral groove and lack the suction apparatus on the podia of the oral surface on the arms.
Range length: 150 (high) mm.
Other Physical Features: ectothermic ; heterothermic ; radial symmetry
The brittle star owes its name to the particular habit of voluntarily breaking off arms and portions of the central disk. There are no reproductive or digestive organs located in the arms, and loss is relatively inconsequential. An arm boken at the central disk can regenerate completely in 10 months. Another interesting fact about the star is the changing of colors from day to night. The adults are much paler at night than during the day.
US Federal List: no special status
CITES: no special status
Development - Life Cycle: metamorphosis
The spiny brittle star has no negative economic effects on humans.
Brittle stars have in the past only affected humans by figuring into the diets of commercially important marine life such as crabs, shrimp, and fish. Recently scientists have been researching the symbiotic relationship with a bacteria that lives between the stars' protective cuticle and inner skin layer. These bacteria protect the star from infection when arms are broken off. This research has great potential for antibiotic drugs and treatment of human diseases.
The spiny brittle star is primarily a deposit and filter feeder, although some of the stars have been reported as carnivorous. The arms of the stars move from side to side, curving upward to intercept detritus and plankton. The food particles are caught in mucous strands strung between the spines and are then moved down to the mouth by the podia. Larger material is swept to the mouth by a looping action of the lateral movement of the arms. The stars feed mainly on pieces of fleshy algae, but some have been known to feed on eggs from damselfish nesting sites. The species possess an incomplete digestive tract, with the mouth also functioning as the anus, which is very unusual for an echnioderm. Feeding is done predominantly at night when the risk of predation is greatly reduced.
Animal Foods: fish; eggs
Plant Foods: algae
Other Foods: detritus
Foraging Behavior: filter-feeding
Primary Diet: carnivore (Piscivore , Eats eggs); omnivore ; planktivore ; detritivore
The spiny brittle star can be found along the eastern coastlines of Central and South America to Brazil, Florida, and the majority of the islands in the Caribbean Sea.
Biogeographic Regions: atlantic ocean (Native )
Spiny brittle stars occupy reefs and reef flats, particularly those abundant in rubble. The stars are also found in seagrass beds and mangroves, under rocks, and in old coral heads. They live in shallow intertidal waters with depths up to 24 meters.
Elevated water temperatures at low tides can kill some individuals.
Range depth: 24 (high) m.
Habitat Regions: saltwater or marine
Aquatic Biomes: reef ; coastal
Spiny brittle stars have testes and ovaries consisting of clusters of gametes in sac-like cavities called bursae. An individual 22 mm in disk length can contain 888,000 eggs. Sexes are separate, however, no sex differences have evolved because no sex recognition is necessary in the spawning process. Fertilization is external. Spawning takes place at night when the predation pressure is lowered. The stars assume a pop-up postion with the central disk lifted above the substratum and release a stream of gametes, either oocytes or spermatozoa, from the bursal slits. The male and female gametes must meet midstream to form a zygote. The fertilized eggs develop into larvae and are moved by the ocean current. After a few weeks, metamorphosis is complete and the larvae become juvenile spiny brittle stars.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Parental Investment: no parental involvement
In Panama this species has been collected in the Caribbean from Galeta Island (USNM E 24060), Margarita Island (USNM E 26511), Fort Sherman (USNM E 24059), Del Parde Island (USNM E 51820), and in San Blas from Miria Island (USNM E 24069) and Pico Feo Island (USNM E 24115).
Clark, H.L. (1921). The echinoderm fauna of Torres Strait: its composition and its origin. Department of Marine Biology of the Carnegie Institute 10: 1-218.
Lamarck, J.B. de. (1816). Ordre Second. Radiaires Échinodermes. Histoire naturelle des animaux sans vertèbres, 2, 522-568.
Say, T. (1825). On the species of the Linnaean genus Asterias inhabiting the coast of the U.S. Journal of the Academy of natural sciences of Philadelphia, 5, 141-154.
Pawson, D. L., D. J. Vance, C. G. Messing, F. A. Solis-Marin, and C. L. Mah. (2009). Echinodermata of the Gulf of Mexico, Pp. 1177–1204 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College S.
LSID urn:lsid:marinespecies.org:taxname:243573Ophiocoma crassispina (Say, 1825) (synonym)
Ophiocoma tumida Müller & Troschel, 1842 (synonym)
Ophiura crassispina Say, 1825 (synonym)
Ophiura echinata Lamarck, 1816
Ophiocoma echinata, the spiny ophiocoma, is a species of brittle star belonging to the family Ophiocomidae. It is the type species of the genus Ophiocoma and is found in the tropical west Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Ophiocoma echinata is a large brittle star, with a maximum armspan of 25 cm (10 in). The slender, tapering arms are densely clad with short spines and are clearly demarcated from the disc. The colour is dark with pale or cream-coloured markings, but the arms never have any red markings.[2]
Ophiocoma echinata is native to the tropical west Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. It is common throughout the Caribbean at depths down to about 30 metres (98 ft). It occurs in seagrass meadows, on reefs and reef flats, hiding under rocks, in cracks and crevices, under coral heads,[2] and inside sponges.[3]
Ophiocoma echinata uses its arms to burrow in the sand and anchor itself in crevices. It holds some of its arms vertically in the passing water current to filter food particles, catching them with the spines and passing them along feeding channels to the mouth. The stomach is entirely within the central disc and is the organ of food storage.[3] Reproduction takes place over a prolonged breeding season with gametes being shed directly into the sea without any synchronisation.[4]
Locomotion involves raising the central disc off the substrate while the tube feet on the arms grip the surface.[3] Despite having no brain and only having a simple, ring-shaped nervous system, O. echinata is able to adopt a coordinated pattern of locomotion in which one arm leads the way and the others act in synchrony to propel it forward. When the brittle star alters its direction of travel, it does not rotate, but instead a different arm becomes the lead arm and the other arms take on the subordinate role. This shows that a radially symmetrical animal can employ fully coordinated, bilaterally symmetrical locomotion.[5]
When attacked by a predator, O. echinata sometimes autotomises (sheds) one or more of its arms. In a back-reef habitat in the Florida Keys, up to 47% of the individuals were found to have missing or damaged arms, and it took about two years for individuals with three missing arms to completely regenerate them. Losing a limb rather than its life is beneficial to the brittle star. Although energy must be diverted to effect the repair and regrowth, the individual should still be able to breed at some time in the future, and the missing arm contributes a renewable resource to the productivity of the reef.[6]
Ophiocoma echinata, the spiny ophiocoma, is a species of brittle star belonging to the family Ophiocomidae. It is the type species of the genus Ophiocoma and is found in the tropical west Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Ophiocoma echinata est une espèce d'ophiures des Caraïbes, de la famille des Ophiocomidae.
Comme la plupart des ophiures, O. echinata est formée d'un disque central mou et aplati autour duquel rayonnent 5 bras allongés en pointe, permettant une reptation rapide.
C'est une grosse ophiure, dont le disque central peut dépasser 3 cm et les bras 15 cm. Celui-ci est généralement plus sombre que les bras, grêles, qui sont souvent tachés de différentes nuances de brun[2], mais jamais de rouge[3].
Cette ophiure présente la particularité d'avoir des organes internes très développés (notamment son appareil digestif), et tous localisés intégralement dans le disque central[4].
Cette ophiure se trouve dans la mer des Caraïbes, de la Floride au Brésil[2],[5]. On la rencontre principalement sur les platiers des récifs coralliens, notamment dans les sédiments grossiers, qui lui offrent de nombreuses cachettes. Mais elle peut aussi se rencontrer dans les herbiers ou les anfractuosités des roches, entre la surface et 25 m de profondeur[2].
Cette ophiure, de mœurs nocturnes et lucifuges, est omnivore opportuniste à tendance planctonivore et suspensivore. Elle utilise ses bras pourvus de fins piquants mobiles couverts de mucus collant pour constituer un filet, qui lui sert à attraper les particules en suspension ; de cette manière, elle peut même chasser sans quitter son abri. Elles peuvent ainsi manger des particules en suspension, des débris organiques, des feutrages bactériens, des œufs, des larves... Là où la nourriture est abondante, elles peuvent vivre en grandes densités[2].
La reproduction est gonochorique, et mâles et femelles relâchent leurs gamètes en même temps de nuit grâce à un signal phéromonal, en pleine eau, où œufs puis larves (appelées ophiopluteus) vont évoluer parmi le plancton pendant quelques semaines avant de rejoindre le sol[2].
Les gamètes sont contenues dans des bourses au sein du disque central, et cette espèce a un fort taux de fécondité : un individu au corps de 22 mm peut produire 888 000 œufs[2].
Comme beaucoup d'échinodermes, ces ophiures ont d'excellentes capacités de régénération, et peuvent perdre un ou plusieurs bras sans danger[2].
Cette espèce est absolument inoffensive pour l'Homme. Elle sert en revanche de nourriture à plusieurs espèces comestibles (crabes, poissons)[2].
Leur système immunitaire est assuré par des bactéries symbiotiques très efficaces, qui pourraient avoir un intérêt pharmaceutique[2].
Cette espèce, abondante dans son aire de répartition, n'est pas protégée. Elle n'est d'aucune importance commerciale[4].
Ophiocoma echinata est une espèce d'ophiures des Caraïbes, de la famille des Ophiocomidae.
Ophiocoma echinata is een slangster uit de familie Ophiocomidae.
De wetenschappelijke naam van de soort werd in 1816 gepubliceerd door Jean-Baptiste de Lamarck.
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