Large Flat Nudibrach or similar creature???

[silverado_4x4]

Today I happend to find an organism which was totally new to me, and that doesnt happen very often. I was pulling an XL turbo snail shell that the snail had apparently passed away. When I moved the shell something moved out of the shell and under a rock. When I flipped the rock much to my surprise was a large nudribranch looking creature that was at least 6-8 inches across!! It was flat and paper thin, formed to the rock, and moved fast to any nook or cranny that it could. Light tan in color, with darker tan/ brown spots.

I pulled the rock and broke it apart to get the critter out. ( not knowing what it was wasn't going to keep it in my reef ) Unfortunately in this process i did inadvertantly damage it, and it split into a couple parts. Only one part is moving and cruising around. I'm assuming that the (brain?) is in this portion. I'm working on getting a decent picture, but if anyone has any insight at all, pics links, etc, please let me know. I really would love to know what this thing is.

 

[johnski]

it is probably a polyclad flatworm and most likely the cause of your snails demise, get it all out

 

[J. Montgomery]

That sounds much bigger than I typically image flatworms and nudis, but what do I know. . .

Did it look like the chiton pictured in this thread?
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1200330

 

[ulthariansamba]

Look like this? If so, get all of it out. Each piece could possibly regenerate into another worm.

 

[FroggyFeet]

That looks like a nasty sucker!

 

[silverado_4x4]

Yup, that would be the one. Thanks for the help!

 

[LeslieH]

Polyclads don't have the same capacity for regeneration as other types of flatworms. They can successfully regenerate the posterior part only if the brain in intact. A median or posterior fragment will not regrow the head region and they cannot regrow into multiple individuals.