Western Spiny Brittle Star

What would you do if you could grow new arms and legs like a Western Spiny Brittle Star?

Latin Name: Ophiothrix spiculata

Western Spiny Brittle Star
Western Spiny Brittle Star at Cabrillo National Monument.

You might have noticed that this small Western Spiny Brittle Star has lost part of a leg. In time this arm should regenerate or regrow. We found this guy in the tidepools at Cabrillo National Monument.

Sea stars have a remarkable ability to regenerate, or regrow, their arms and tube feet. Most kinds of sea stars need at least part of their central disk to be intact in order to regenerate arms, but a few tropical species can grow an entire body from just a severed limb. Regeneration of arms is not a fast process; it can take up to a year for larger sea stars.

Western Spiny Brittle Star diagram
Western Spiny Brittle Star diagram

Western Spiny Brittle Star Stats

Description: Spiny.  Orange, yellow, tan, brown, green, variously patterned. Long, thorny spines on margins of arms and disk.

Size: Disk diameter ¾ in (19 mm), arm length 6 in (15 cm)

Habitat: water depth 0.35 m Under rocks, in crevices and mats of algae or invertebrates; from low-tide line to water 660 ft (2012 m) deep

Range: Kelp holdfasts and clumps of bryozoans and worm tubes are often writhing masses of Western Spiny Brittle Star arms. 

Diet: Brittle stars are mainly detrivores (detritus-eaters); they eat decaying matter and plankton. Some brittle stars can also kill small animals. They push their stomach out through their mouth (which is located on the underside of the disk of the brittle stars) and digest the prey (there is no anus).

Fascinating Fact: Western Spiny Brittle Star’s anchor themselves with spines of one or more arms. They then extend their other arms into the water for filter feeding.

Fascinating Fact: If a brittle star’s arm is cut off, it will regenerate (regrow).

Scientific Classification

Kingdom: Animalia
Phylum: Echinodermata
Class: Ophiuroidea
Order: Amphilepidida
Family:  Ophiotrichidae
Genus: Ophiothrix
Species: Ophiothrix (Ophiothrix) spiculata

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