Morphology

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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

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