April 2005 Unknown

WINNERS:

Our April contest, like the month before, proved to be a bit of a stumper. Many readers recognized this beautiful organism as a plumed annelid worm, and many submissions correctly identified the family, Serpulidae. Genus names like Spirobranchus, Sabellastarte and others were submitted, but a quick check on Google images will show the differences. Thanks for your submissions.

 

Thanks to all of those who submitted an entry to this contest.

Beautiful End to a Hard Tube

Some worms of the Phylum Annelida, Class Polychaeta, live in tubes. These tubes can vary from the large (2cm diameter, 0.5 meter long) tubes of the "feather duster" worm (Eudistylia), to the parchment tubes of the burrowing worm Chaetopterus, to the tiny 3mm spirals of the spiral tube worm, Spirorbis. The species shown here, Serpula vermicularis, is a common West Coast tube worm that lives in a strong, calcified tube it builds from calcium carbonate extracted from the sea. The tubes are typically about 5-7 mm in diameter and up to 8 or 10 cm in length. The worm lies hidden inside the tube with only the feeding tentacles exposed. These finely-divided arrays of soft tissue form a beautiful 'floral' arrangement, with a single trumpet-like cone of modified tentacles in the center (the red cone). Each fine branch is covered by cilia, and each contains a groove that channels captured food (detritus and some plankton) into larger cilia-lined grooves leading to the mouth. The cone-shaped structure serves as a 'plug' - it is the last portion of the tentacles to be pulled back into the shell when the animal senses danger. The feeding mechanisms of plumed worms and other annelid features can be viewed on our program, Branches on the Tree of Life: Annelids.
 

For a concise and revealing teaching video about Arthropods, get our video/DVD: Branches On the Tree of Life: Arthropods. For a rich overview of marine intertidal ecology, see our program: The Biology of Seashores.