ID: Some Sort of Filter Feeder, Feels Like a Zoa

[GuyInCentralVA]

I have no idea what this is. I now have quite a few popping up, usually in spots sheltered from the light (under the overflow), but some are in direct light. They look like an undulated leathery collar with filtering filaments around the inside edge that will close up if you poke them. They feel slimy and squishy like a zoanthid. Largest ones are roughly 1/2" or so in diameter.

http://imgur.com/a/dHMVi

 

[Sugar Magnolia]

Tunicate, pretty cool!

 

[GuyInCentralVA]

I don't think it's a tunicate. There are no siphons, the filter feeding filaments stick out from around the edge. I don't see any pictures of tunicates that look anything like this.

 

[Sugar Magnolia]

The syphon is the hole at the top. That looks to me like the beginnings of a colonial tunicate (sea squirt) colony.

 

[GuyInCentralVA]

That's one individual, there are many of them throughout the tank. Tunicates have an incurrent and outcurrent siphon. These don't have either. I have never seen or heard of a tunicate having branching filter feeders that reach out into the water. If you think it's a tunicate, what type?