Has anyone ever seen this thing before?

[awpong]

http://i558.photobucket.com/albums/ss28/awpong/WeirdHitchhikerID.jpg

Can anyone ID this thing for me?

Each tentacle is a little less than a cm in length, and the entire creature lives inside of that sand-tube. It will retract on contact.

I've never seen anything like this before and haven't been able to ID him. He's been in my tank for about a year and hasn't spread, this is just the first time I've been able to photograph him. He was originally attached to the rock base of one of my SPS, but he moved after I buried him in the sand.

[awpong]

Here is a quick video of this thing: http://youtu.be/Xb1i9xWjoPo

Be sure to watch the video in HD.

I blow it with water at the end of the video to show that it retracts into it's tube.

[LeslieH]

I suspect it's some kind of clam or scallop. Send Pagojoe a PM - he's the best mollusc person here.

[wenwillwego]

Not that I'm an expert on these things, but scallop is the first thing I thought too. Cool critter!

[awpong]

Hmm. It doesn't really look like a scallop to me, but I went ahead and PM'd Pagojoe to get his input.

[awpong]

Mystery is has been solved. Thanks to WWM, this little guy has been identified as a Sabellariid (family Sabellariidae) in the genus Lygdamis.

Here's a cool paper they sent me describing the anatomy, habitat, and behavior of these worms:
https://repositorio.uac.pt/bitstream/10400.3/142/1/pp37_42_Nishi_Nunez_17A.pdf

[awpong]

I suspect it's some kind of clam or scallop. Send Pagojoe a PM - he's the best mollusc person here.
Leslie, I'm surprised you didn't suggest Lygdamis. In all of the research I've done on this guy, your name keeps popping up everywhere.

[Sugar Magnolia]

Mystery is has been solved. Thanks to WWM, this little guy has been identified as a Sabellariid (family Sabellariidae) in the genus Lygdamis.

Here's a cool paper they sent me describing the anatomy, habitat, and behavior of these worms:
https://repositorio.uac.pt/bitstream/10400.3/142/1/pp37_42_Nishi_Nunez_17A.pdf

That's pretty amazing! It never ceases to amaze me the things we find in our little boxes of ocean.

[pagojoe]

The photo tricked her, lol. That, and the positioning of the worm. It's overlying the opening of a couple of Spondylus (I wonder why?), and many of the related bivalves have similar tentacles that extend from the opening. I had never seen one with such fine tentacles/bristles, though. The description makes it sound like you should see it extending from a tube, which adds to the trickiness of ID'ing it. Glad you found it!


Don

[LeslieH]

What he said! :-D I was staring at the rock & ignored the sand tube. Also, the only Lygdamis I know well are solitary individuals living in upright burrows in sand so the positioning of this one on rock is new to me.

I'm going to steal your photo so I can use it for future reference if that's okay. :-)) But I'll put your real name on the file (if you let me know it) so you get credit.

[awpong]

What he said! :-D I was staring at the rock & ignored the sand tube. Also, the only Lygdamis I know well are solitary individuals living in upright burrows in sand so the positioning of this one on rock is new to me.

I'm going to steal your photo so I can use it for future reference if that's okay. :-)) But I'll put your real name on the file (if you let me know it) so you get credit.

Sure, you can use it. My name is Alex Pong.


I also just sent an email to Eijiroh Nishi to see if he can identify which species this is. He and his predecessor discovered and named almost all of the known Lygdamis species, so I'm curious if he's seen this guy before.

[LeslieH]

Ejiroh's an expert on sabellariids but he only described 2 of the 20+ species in the genus. Most of them have never been seen alive so he may not be able to match your photo to a known species. And I bet you anything that he'll want the worm to play with! :-D

[pagojoe]

Side note: looks like you have a cute little nudibranch associating with your sabellariid. See that little pink thing with the white stickers just to the right of the lower worm (or worm branch, or whatever you'd call it)? I'm pretty sure that's Marianina rosea. It's actually the first thing I saw in your pic.

http://www.seaslugforum.net/find/marirose

Cheers,



Don

[awpong]

Side note: looks like you have a cute little nudibranch associating with your sabellariid. See that little pink thing with the white stickers just to the right of the lower worm (or worm branch, or whatever you'd call it)? I'm pretty sure that's Marianina rosea. It's actually the first thing I saw in your pic.

http://www.seaslugforum.net/find/marirose

Cheers,

Don

I wish he was something that cool, but alas, he is just the head of a small bristle worm poking out of the rock.

[pagojoe]

HMMM, I wonder who's mimicking whom...