Giant Feather Duster Worm, Eudistylia polymorpha

The Giant Feather Duster Worm (Eudistylia polymorpha) is a species of marine polychaete worm of the Sabellidae family. Its range extends along the western coast of North America, from Alaska to California. It is most commonly found in the intertidal zone in tide pools and in the neritic (coastal) zone at depths up to 1,375 feet. It is often found in groups along rocks, reefs, pilings, wharves and marinas. Its common name comes from the crown of tentacles extended when the animal is under water.

This worm grows up to 10 inches long and 0.5 inches in diameter and lives within a tube. The tube is parchment-like and composed of sediment cemented with mucus. The worm is brownish in color and translucent. On rocky shores, this worm may be hidden in a crevice and difficult to dislodge. The feeding appendages of this worm also serve as gills, and are often reddish or brown, banded with paler sections. Coloration can vary, but the most common coloration is maroon with orange tips.

The feather duster has two eyespots that alerts it when sudden shadows or movements occur nearby. This enables the crown to be retracted into the tube very rapidly when danger threatens. The posterior segments of the worm bear hooked bristles which help anchor it in its tube. This species can be easily distinguished from the very similar E. vancoveri by the cleft in the crown.

This species is a filter feeder, catching food particles with its pinnately (feathery) branched radioles (tentacles). It prefers moving water so a constant stream of particles comes within reach. These particles are trapped by the feeding appendages and moved by cilia down grooves in the radioles to the large, funnel-shaped mouth. Undigested debris is ejected through the fecal groove located at the base of the gut. Any particles to large to be ingested often get incorporated into the worm’s tube structure.

Reproduction occurs in the spring and fertilization is external. The gonads are on the dorsal side of the abdomen and the reproductive cells mature in the gut and then are passed through the fecal groove and ejected into the water column. The larvae grow rapidly and settle on surfaces after three to four weeks.

Image Caption: Giant Feather Duster Worm, Eudistylia polymorpha, Pacific Ocean, offshore Hawaii. Credit: OAR/National Undersea Research Program (NURP)/Wikipedia