Brittle star

Microphiopholis atra

Family Amphiuridae - brittle stars

Distinguishing
Characteristics
Round disk (missing up above pictures); 5 narrow arms distinctly set off from disk in between lobes; arm segments with 3 spines on each side; 5 pair of plates (radial shields) on dorsal disk, each shield triangular to oval in shape, longer than wide, pairs joined at least at distal ends; color tan to gray, no dark banding on arms, scales on upper surface of disk larger than on lower surface; disk may appear to be inflated or swollen; disk may be missing, as in this specimen, many times discarded when animal is disturbed (disk later regenerates).
Similar Species
All brittle stars have a central disk with usually 5 arms distinctly set off from disk (see the banded brittle star). The easiest way to distinguish between species is to look at the radial shields and scales on the disk. Lacking the disk, the shape of the arm scales, the number and shape of the arm spines, and several internal structures must be examined.
Habitat
Gulf, sandy bottoms
Maximum Size
15 cm (6 in)
Other Common Names
Previous Scientific Names
Amphiodia atra
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