Golden and groovy

 

This weekend we photographed some beautiful peanut worms (sipunculans).  This is Themiste pyroides, a local species that can be found in the low intertidal zone of rocky shores.  They nestle in crevices so they can be hard to see, but when their crown of tentacles is fully extended, they're pretty spectacular.

Eric photographed one individual with mostly golden-colored tentacles (above).  This individual also retracted its tentacles, revealing its introvert with dark hooks (see below; the hooks look like tiny chocolate chips).  (Peanut worms can withdraw their tentacles completely.)  We haven't been able to find any information about how these little hooks might be used in this species.  Do you have any ideas?

 

Then I photographed a different Themiste, this one with purple tips on many of its tentacles.  Here's a close-up:

 

Themiste uses this array of branched tentacles to capture food from the water.  In the next photo (below), look for the grooves in the center of the branches (especially on the right side of the image).  The tentacles are covered in cilia and mucous, and the grooves are probably involved in food gathering, but we haven't been able to locate a detailed description of the feeding behavior.