What is this?

[jjwalker]

Hi,

I noticed this worm thing eating a dead hermit crab last night. It only comes out at night so I had to use a flash to capture the photo. The hermit crab is incased in a web .

Any ideas on what it is?

Thanks

http://reefcentral.com/gallery/data/500/80596worm_thing.jpg

[CrystalAZ]

Looks like a peanut worm. They are nocturnal scavengers and will suck back in if the light hits them. Good guys.

Crystal

[iCam]

Crystal, do you feel pretty sure that it's a peanut worm? Any that I see are always smooth. The specimen in the above photo seems to have leg-like protrusions.

http://www.hangarspace.co.uk/chrisreef/photos/thing.jpg

Also, I didn't suspect that a Sipunculid would be eating a dead hermit crab.

[CrystalAZ]

Hmmm... I missed the protrusions. Maybe I am wrong (certainly wouldn't be the first time! :D )

Re-reading the post, the "web" sounds like a vermitid, but that sure doesn't look like what I know as a vermitid. ??

So I am stumped.

This sounds like a question for Dr. Ron. :)

Crystal

[iCam]

The web does make it sound like it could be a vermitid. I can't tell if the smooth area at the base of the specimen protruding from the rock is part of the worm's body, or part of a calcareous shell.

[bertoni]

Do you mean "vermetid" as in vermetid snails? This animal looks more like a worm of some sort.

[iCam]

Originally posted by bertoni
Do you mean "vermetid" as in vermetid snails? This animal looks more like a worm of some sort.

Vermetid snail:

http://homepage.ntlworld.com/k.davis11/Images7.04/vermitid.jpg

[bertoni]

Vermetid snails can't retract as much as a worm, since most of what you see is a calcium carbonate shell, as in the picture shown.