Fireworm variations

[Frank O]

While diving and snorkeling in Roatan during the past week, I came across a number of fireworms. Most were the bearded type such as this ~4-incher:

Bearded fireworm

However, we saw one creature on a night dive that I'm still scratching my head over. Unfortunately I didn't take my camera on that dive, so I don't have a picture of it. It was much larger than the other fireworms we saw -- maybe 10 inches or so -- and was quite dark (I'm remembering it as almost black). I remember numerous segments, but am not remembering any beard-type fringing. It was moving at a moderately good speed, and I remember two little poking-out things on what appeared to be the head end (don't know the terminology here -- sort of like what on a nudi you'd call rhinophores).

I see that Humann's Caribbean invert book says some of the fireworms can get up to a foot in length, but I'm not seeing any there that are as dark as I'm remembering this one. Does this description suggest anything to anyone? Thanks for any input.

 

[LeslieH]

It doesn't sound like a fireworm or any other member of the family Amphinomidae. The head appendages in this family are very small and can't be seen without a magnifier. But what is it? I don't know - your description is too vague, sorry. Take a look at these urls - do any of the worms looks familiar?

http://www.nhm.org/guana/bvi-invt/bvi-surv/worm-tit.htm
http://www.nhm.org/research/annelida/index.html

 

[Frank O]

Thanks for the comments, Leslie. I looked at those links and didn't see anything that rang the bell.

I apologize for my description being somewhat vague; the salient points are (a) ~10 inches long, (b) dark coloration (almost black), (c) very distinct segmentation -- almost like a series of linked flattened spheres, (c) two dark, skinny head appendages (feelers or whatever), and (d) freely moving (not anchored in any way).

The single feature that stood out to me was that it was very dark compared to most of the other worm pictures I've seen.

 

[LeslieH]

Sorry, still way too vague although understandable under the circumstances! Two head appendages is the wrong number for all of the big free-living worms* I can think of so maybe you couldn't see all of them? Could it possibly have been a cucumber of some sort with 2 of the feeding tentacles extended?

*worms = polychaetes

 

[Frank O]

Either of those alternatives sound plausible. Re the first, do any large, dark free-living worms found in Roatan come to mind? Re the second, this was in a shallow lagoon where I also noted a couple of big donkey dung sea cucumbers, so I suppose it could have been a baby one of those -- though it seemed a lot more spry that the cukes I saw.

 

[LeslieH]

I was thinking more of the beaded sea cucumber Euapta lappa or something like it: http://www.critterzone.com/gallery/underwater-sea-cucumber-beaded-gallery.htm

Some eunicids are very dark, have 5 head appendages, and some travel freely at night. That would be my first guess for a poly.