Gorgonocephalus eucnemis

Background

The basket star Gorgonocephalus eucnemis has a central disc that can reach 14 cm across, from which five pairs of arms extend. These arms split repeatedly into smaller and smaller branches.

The animal’s color ranges through shades of white and beige, with the disc often being darker. Beneath a rubbery, fleshy skin lies an endoskeleton made of calcified ossicles. Tiny hooks and spines covering the arms help the star grip and handle food.

To feed, it perches in an elevated spot and spreads its arms like a net, held sideways to the current. The twisting, coiling branches make it look like a living bush. It captures small crustaceans like northern krill, copepods, chaetognaths, jellyfish, and bits of detritus. Once trapped, prey is wrapped in a knot and immobilized by mucus.

The branches then coil further to bring the food to the mouth, located on the underside of the central disc. There, the branchlets pass through a comb-like structure that scrapes off the food. Because there is no anus, any undigested material is pushed back out through the mouth.

Each basket star is either male or female. After spawning, the larvae drift as plankton, carried by currents. During the day, the star stays hidden, often among toxic sponges that offer protection, though fish and crabs sometimes eat it.

It tends to return to the same spot repeatedly. It commonly lives alongside sponges and soft corals of the genus Gersemia, hiding under them or in sponge folds by day and using them as elevated perches for night hunting. In Puget Sound, young basket stars have been found living and feeding inside the pharynges of Gersemia rubiformis polyps, only leaving when large enough to survive on their own.