Luidia foliolata

Lore & Background

The sand star has a small disc and five long, flattened arms with tapering tips. Its arms have rows of large marginal plates, each with several spines, but these are not visible from the aboral (upper) side. The tube feet have no suckers, ending instead with blunt points. This starfish seems to be easily damaged, often breaking into pieces if raised from the seabed by trawling, and even when brought up intact it frequently has missing or regenerating arms, perhaps from attacks by predatory crabs or fish.

The sand star is well-camouflaged on sandy and muddy seabeds, often half-covered with sediment. It can create a shallow depression and work its way under bivalve molluscs, polychaete worms, brittle stars, and sea cucumbers on which it feeds. Unlike some other starfish, it cannot evert its stomach, so is limited to smaller-sized prey. It is agile and can right itself rapidly if turned upside down. Its long, pointed tube feet are specially adapted for movement over soft sediments but lose traction on steeply sloping rocks. It is a fast traveller, moving across the seabed at 280 cm per minute, many times faster than slow species such as the leather star (Dermasterias imbricata), which moves only 15 cm per minute.

Reader's Guide

The sand star is significant as a fast-moving predator of soft-sediment communities in the northeastern Pacific. Its tube feet, lacking suckers and ending in blunt points, are a specialized adaptation for locomotion on sand and mud, enabling it to travel at 280 cm per minute—far faster than many other starfish. Its inability to evert its stomach restricts it to smaller prey, distinguishing its feeding ecology from that of other starfish. The species is also notable for its fragility; it often breaks apart when trawled, and many individuals show signs of arm loss and regeneration, likely due to predation by crabs or fish. This fragility and regenerative ability are key aspects of its life history. The sand star can be confused with Astropecten verrilli, but in that species the large marginal plates are visible from above, whereas in Luidia foliolata they are not. Its range extends from Alaska to the Galapagos Islands and Nicaragua, and it is found at depths up to about 600 m.

Did You Know?

• It can move across the seabed at 280 cm per minute, much faster than the leather star.
• It cannot evert its stomach, so it is limited to smaller-sized prey.
• It is often found with missing or regenerating arms, possibly from attacks by predatory crabs or fish.