was diving the end of Tenesh last week--- (07/16/09)on safety stop, Cristina Roman and I saw a huge conch following a 12-14" "worm", a little darker than the sand in color---head end rounded and smooth, butt end looked like : how do I explain this?  When you buy the weiners that are joined together---or boudin---the clamped part---thats the only way I can describe it.  I picked it up---I know, I know---thats a no-no--but I have been diving for 30 years, and its the first one I have ever seen like this.  It was like holding a feather in my hands---no weight at all----I put it back down and watched it move over the floor of the ocean just like a worm does in dirt.  The conch was following its every move.  The photographer had already gone to the boat, so there are no pictures.  Does anyone have any idea what it was from this description?

Here's some insight/background:

Most of the Caribbean unsegmented worms are small -- less than a few inches long. The ong ones are the ribbon worms, but there's little info on them in the standard ID books. Perhaps a post at Scubaboard's "Name that Critter" forum will lead to a knowledgeable person.

If it had bumps or segments, it could have been a juvenile sea cucumber like the beaded, which is common in Cozumel, doesn't have tube feet, but does have small tentacles at its mouth that you should have noticed. As you had no ill effect after picking it up, you can eliminate the fireworm families. The other segmented worms that grow to 12" or more have obvious tentacles and are rarely seen. These are: The Thing, some of the Eunices, Spaghetti worms, and Medusas worms.

Wish I could have been more helpful. Buen suerte.

I have looked and looked for it on dozens of marine boards with no luck whatsoever.  I have elimated several---its just my luck that the cameraman was already up.  I can tell you it was smooth---no spines or lumps of any kind.  Cristina told me it is the first one she has seen in Cozumel, and she has been a dive master there since the early to mid 80's.   She had seen one over by the Bahamas---

I'm not sure either.  We have a trip soon with guests who wish to dive Punta Tunich and we will keep an eye out.

Peace,
Dennis

did it look something like this?




The striking dark-striped white body of Synaptula lamperti makes an attractive picture against the colored background of the sponges on which they are exclusively found. (Photo by Robert Fenner)

Synaptula lamperti is a medusa worm, or a "footless" sea cucumber, in Indo-Pacific waters (same places as the Red Lionfish!) The common Caribbean species are Euapta lappa (the beaded sea cucumber) which is lumpy rather than ribbonlike, and Synaptula hydriformis (no common name, formerly classified as Holothuria hydriformis) which burrows in shallows and I don't know what that one looks like. Both of these species live in Cozumel.