What the heck is this worm?

[theJ]

Can someone help me ID this guy?

 

[returnofsid]

Oh wow...interesting critter. My first guess would be Peanut Worm...but I'm only half convinced that's what it is. Any chance of getting a pic of it's head and mouth? If you can figure out which end that's on...lol. How long is it?

 

[theJ]

it was about 3 inches long, the head/mouth is on the right side. He didnt have extending jaws really, but more like a feather duster type mouth, it would come out, grab a mouthfull of sand, and the equivilent amount would come out the other end. I have ID'd a peanut worm in my tank, and this guy looks nothing like it. The peanut worm has 2 definate colors a sand colored belly, and a black top to him. He also had extending jaws that came out to nip at the sand/rock. The one in the picure Im trying to get an ID on looks more like an earthworm, but transparent!

 

[returnofsid]

Peanut worms do usually have 2 distinct colors...however, they also have a mouth like you described, with the feather duster like appendage. I've got a Peanut Worm that I love watching eat. It extends it's jaw out and then extends it's "feathers" out and then retracts it all. It's rare to see an entire Peanut Worm though as they keep most of their bodies burrowed in rocks. Mine does have 2 distinct brown colors. Hmmm here's a thought...could it be a feather duster worm that some how or for some reason has left it's tube?

 

[theJ]

i havent had any feather dusters that large in my tank before, only the small ones that attach to rocks. What do the large featherduster worms look like out of the tube? anyone got pics? One thing to note, you can see what it eats, if you zoom in on that pic you can see his whole body filled with sand. Do feather duster worms munch on sand when they loose or are trying to grow a crown?

 

[LeslieH]

There's no sign of segmentation so it's not a polychaete. Without seeing the head my three choices would be sipunc (not all of them live in rock), echuroid, or enteropneust.

 

[returnofsid]

I knew Leslie would eventually chime in with her wealth of knowledge!!! Get her a head pic!!!

 

[theJ]

Very gross but not gross lke this spunic. The head (if its on the left in this pic) has a definate 'head' look to it, :
http://www.nhm.org/guana/bvi-invt/bvi-surv/images/educ-i01/stu-125.htm

I dont belive it was echiuroid, because it didnt have any setae: http://www.rosario.wwc.edu/inverts/Echiura/Echiurus_echiurus1sDLC2005.jpg
Also he was really translucent, i could pick out many individual grains of sugar sand inside his body, unlike the nasty batard in that pic.

it doesnt have a head (or any collar at all) like this enteropneust either: http://www.mbari.org/expeditions/vance/images/T1011-08_22_32_18.jpg
http://pharyngula.org/index/weblog/comments/torquarator_bullocki/

I will try my best to snap a pic, but this is the first time ive seen this guy, it might be a very long time before i see him again, thanks for your help!

 

[theJ]

bumping, with a side of fries please

 

[LeslieH]

Both sipuncs & echs come in a variety of sizes & body textures. The Guana sipunc is unusually large - most are much much smaller. Setae are normally retracted on living echuroids & hard to see; if your animal is an echuroid it's probably not the body but rather the proboscis which gathers food. The 2 enteropneust websites are focusing on a very bizarre deep sea animal; shallow water species have a simple acorn shaped head (which may be elongated). It really has the look of a capitellid polychaete but it does seem to lack segmentation which rules out that group.

 

[theJ]

ahh very good point. This one DOES look a lot like capitellid polychaete, but you are right, no sign of any segmentation. Thanks for helping out Leslie, I will try my best to get you another pic of the head, but I wouldnt be surprised if i never see him again.