New type of Feather Duster?

[AMDphenomx4]

Well, today when i went to my LFS and looked closely at a rock, i saw a small shine from thinner than hair fibers in the shape of a feather duster. The middle had 3 moving brownish tentacles with 2 being longer. The "feathers" were like a non lit fiber optic cable with the light giving rainbow coloration on it. I know it is alive as their was a second on a rock in a different area. It was the size of a hitchhiking featherduster, with the feathers around twice the length.

 

[jmski333]

you know everyone is going to ask you for pictures right?

 

[LeslieH]

Nope, not a feather duster but it is a polychaete in the family Flabelligeridae. You're exactly right to describe the "feathers" as being like non-lit fiber optic cable. Those are the setae (= bristles) characteristic of polychaetes. In a few groups like Flabelligeridae & Aphroditidae (sea mice) they are indeed naturally occurring fiber optic filaments. What you saw were the setae of the anterior segments which are much longer than those in the rest of the body & pointed forwards. Along the rest of the body the setae are short & are used to move the animal inside it's burrow & to hold tight if a predator tries to pull it out. The moving brown tentacles are the feeding structures which spread strings of mucus over the long setae to form a sticky net. Particles floating through the water are caught on the net and then the tentacles roll up the net & carry it to the mouth. Flabelligerids are common in rocks & coral rubble but because they're small & the setae are clear unless the light hits them just right people don't notice them very often. Here are two previous posts about them:

http://reefcentral.com/forums/showthread.php?t=1316505&highlight=flabelligeridae
http://reefcentral.com/forums/showthread.php?t=833539&highlight=flabelligeridae

 

[AMDphenomx4]

Dam, your good.

 

[kingfisher62]

LeslieH asked me to submit these pics to this thread. The first 2 pics are what she asked me to send I am not sure why because it does not seem to fit the description as well as the second 2 photos I am sending. In the fourth picture I want to point out the worm to the left of the feather duster.

 

[LeslieH]

OOPS! I meant only the last one Kingfisher. My bad...... But thanks for posting the last two which are exactly right.