Daisy Brittle Star

The daisy brittle star has a star-shaped body that is radially symmetrical and supported by a hard endoskeleton made of calcium. Its 5-7 spiny, jointed arms are attached to a central disk that contains the mouth and jaws, stomach, and saclike body cavities called bursa.

A characteristic of all echinoderms is the water vascular system. Water-filled canals branch out from a ring canal that encircles the gut. The canals lead to the brittle star's tube feet, which it uses for grasping and moving objects. Special sensory tube feet are used for sensory perception.

The mouth is made up of five moveable jaw segments, and food enters the mouth and goes directly into the stomach. There is no intestine and no anus, thus absorption and excretion is carried out by the bursa located at the base of each of the arms. Like all the echinoderms, the brittle star has no head and eyes, nor do their bodies contain a brain or a heart.

Daisy brittle stars have a disc diameter of up to 2 cm and its arms grow to about 8 cm long. It can grow a diameter of 5-7 mm in two years. Usually a reddish shade, the daisy brittle star frequently has dark bands on the arms, although colors and markings may vary. The upper arm plate of this species is ringed by small scales and 5-6 arm spines. The disk is covered with fine, blunt spines and large oval plates. When handled by humans or predators, the brittle star's arms can detach, hence the name.(Bernhard 1972, Gosner 1978, Kistner 1999)

Other Physical Features: ectothermic

Because brittle stars tend to be shy, they are usually found hidden within or beneath rocks in tidepools, or burrowing in the sand and mud. Usually they can be found in the lower intertidal zones up to almost 5000 feet deep.(Gosner 1978)

Aquatic Biomes: reef ; coastal

The most common of all brittle stars, they can usually be found worldwide in marine environments. A specific area to see these creatures is the Arctic South to Cape Cod and sometimes to East Long Island Sound.(Gosner 1978)

Biogeographic Regions: atlantic ocean (Native )

The greatest concern for brittle stars involves the conservation of their habitats. Pollution and disruption of the shores that they live in is harmful to not only the brittle stars but also to all the other marine animals dependent on this lifestyle. Currently hundreds of conservation organizations across the world are working to lower the level of risk being inflicted upon the marine environment. As long as people can be made aware of the dangers of pollution and the importance of conservation, the amount of marine life being destroyed can be minimized.

Brittle stars have not had much of an impact upon humans. During the eighteenth century, Indonesians would cook and eat the brittle stars, but today they are simply more of an ornamental species, mostly enjoyed through observation in their habitats. Unlike the starfish, brittle stars are not harvested for souvenirs due to the fragile nature of their structure.(Kistner 1999)

Their main source of food are small bits of decaying matter and microscopic organisms. Sometimes they feed upon larger prey such as polychaete worms and small crustaceans.(Gosner 1978)

Sexes are separate, and brittle stars tend to spawn at the end of the summer. The walls of the bursa are coelomic and contain gonads that discharge sex cells into the water for fertilization. The larvae is called the ophiopluteus and freely swims in the plankton until it transforms into the juvenile stage, when it settles on the ocean bottom. Brittle stars can also reproduce asexually; if a portion of the star breaks off and contains the central disk, it can regenerate into a new brittle star.(Balser 1998, Kistner 1999)

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Woods Hole, Maine

Rocky intertidal or kelp holdfasts

Biology/Natural History: This is the main species common on rocky shores in our area. Others can be found in gravelly areas or in areas with boulders interspersed with sand. They feed by capturing food with their tube feet, by picking up detritus, or by mucus secreted by the rays. Predators include fish and harlequin ducks. Ovaries are red and testes are white. In our area they may spawn in Jan-March, July, October, or November. In the USSR, spawning seems to follow a lunar cycle. Metamorphosis from the larval stage does not occur until 83-216 days after fertilization.

This brittle star is distinctive in this area because the plates on the aboral surface of the rays are separated from one another by smaller supplementary plates. The rays have five spines on the lateral plates, the middle of which is the largest. Color and pattern are extremely variable. The color usually includes red stripes or blotches, usually interspersed with brown but sometimes with green. Flora and Fairbanks state that it can sometimes be black and white or gray and brown. The oral surface is whitish.

Depth Range: Lower intertidal to 2000 m

Geographical Range: Worldwide, especially north temperate. On our coasts, Bering Sea to Santa Barbara, CA; most abundant in the north.

How to Distinguish from Similar Species: This is the only local species of brittle stars that has the supplementary plates.

Ophiopholis aculeata, the crevice brittle star or daisy brittle star, is a species of brittle star in the family Ophiactidae. It has a circum-polar distribution and is found in the Arctic Ocean, the northern Atlantic Ocean and the northern Pacific.

Ophiopluteus larva

Arctic to Cape Cod

Circumpolar

Common on the lower shore and sublittoral region of the northern coast of British Isles and down to at least 100 m depth off western coasts; absent from the English Channel and southern North Sea

intertidal, bathyal, infralittoral and circalittoral of the Gulf and estuary