Eudistylia vancouveri (Kinberg 1866)

How to Distinguish from Similar Species: In Eudistylia catharinae the notopodia of the first few abdominal segments are shorter than the tori of the posterior thoracic segments. In Eudistylia polymorpha the dorsal edges of both lobes from which the radioles originate have a cleft; plus its prostomial cirri are reddigh borwn to maroon and tipped with orange. Other species also do not have the distinctive green and maroon bands on their radioles.

Often in large clusters attached to crevices of boulders and bedrock, or on floats or pilings; and on vertical rock faces and surge channels in heavy surf.

Geographical Range: Alaska to central California

Depth Range: Low intertidal to 20 m

As with all sabellids, this species lives in a soft, leathery, parchmentlike, or mucus tube which it secretes. Few if any of the body segments are longer than wide when contracted. Their dorsal surface is not covered by paleae, elytra, or felt. The peristomium has several featherlike radioles that are closely associated with the mouth and used for feeding, forming a feather-duster like structure. It does not close its tube with an operculum. Eudistylia vancouveri is a common, large species. Most of the radioles are unbranched, but a few are branched. They have no conspicuous, curled ocelli on the radioles. The first 5 or 6 thoracic neuropodia have avicular uncini and pickaxe-shaped setae. The lobes from which the radioles arise are spirally coiled, and the dorsal edges of the lobes from which the radioles originate do not have with a cleft. The notopodia of the first few abdominal segments are shorter than the tori of the posterior thoracic segments. The radioles are banded green and purple or maroon. Up to 25 cm long and 1.2 cm wide, in a tube up to about 45 cm long. Plume of radioles expands to about 5 cm diameter. Note: Sabellids such as this species have a groove which carries fecal wastes from the anus to the mouth of the tube. On the posterior part of the body this groove is ventral, but at the anterior end it becomes dorsal. This makes it easy to recognize the dorsal side.

Biology/Natural History: Although they do not have large ocelli as found in some other plumeworms, this species is highly light sensitive and will withdraw quickly into the tube if a shadow passes over it. Often anemones are found feeding near the top of the tube. This species may hybridize with Eudistylia polymorpha. Its blood contains chlorocruorin instead of hemoglobin. They can regenerate their radioles if a predator nips them off. The radioles of members of Family Sabellidae contain a food groove with a stepped cross-section that serves as a size-filter. The smallest particles, which fit in all the way to the bottom of the groove, are usually eaten. Moderate size particles, in the upper parts of the groove, are often glued together to build the tube. The largest particles, too large to fit within the groove, are usually rejected. The radioles are also used for gas exchange but the circulatory pattern within them is unusual. Instead of having afferent and efferent vessels, the radioles have a single branchial vessel in each radiole which the blood flows in and out of. Sabellids possess giant nerve fibers running down their body which allows them to retract rapidly into their tube if disturbed.