Spiny Comb-Star, Astropecten irregilaris

The Spiny Comb-star (Astropecten irregilaris), is a species of starfish in the Astropectinidae family. It is found in the Atlantic Ocean and the Mediterranean Sea. It lives on mobile seabed (sandy, muddy or gravely) and remains buried under sediment during the daytime. It is a very common species in all kinds of mobile seabed from 4 to 4,000 feet deep. It is active in the late afternoon and at night.

Specimens from the Atlantic and Mediterranean show differences in the superomarginal plates. The Mediterranean populations have superomarginal plates that are devoid of spines, while Atlantic populations have one spine for each superomarginal plate.

The inferomarginal plates are short, thin, fine-spined, highly mobile and white in color. The spines on this creature are not as rigid and parallel to each other as seen in other species of starfish. The aboral (back) side of this specimen is usually pink, pink-yellow, or gray, or often violet towards the end of the arms. Sometimes small dark spots are seen in the central disc.

Sometimes there is a bulge on the central disc that is highly developed. The bulge protrude from the sediment where the animal is hidden. The diameter of the Spiny Comb-star is about 4 to 4.75 inches in diameter, with a maximum of 7.5 inches.

This species is often confused with Astropecten aranciacus due to similar color. Closer inspection of the superomarginal plates, however, makes it easy to tell the two species apart.

This sea star is a carnivore that feeds mainly on mollusks, which it catches with its arms and then takes to the mouth. The prey is trapped by the long, moving prickles around the mouth cavity. It hunts mainly at night, but can often be seen in the late afternoon hunting food as well.

Image Caption: Astropecten irregularis pentacanthus. Credit: Rpillon/Wikipedia(CC BY-SA 3.0)