Not so solitary horn coral...who might be its buddy?

[Pippa]

Hello everyone. As usual, I need your help with one of my finds.

It seems this small rugose coral has a buddy. At first I thought the the tiny "bump" was just a bit of debris sitting on top of the coral. But now that it's enlarged, it looks to me somewhat similar to a crinoid. I'm not really sure though, I've never seen a crinoid preserved anything like this. 

Surely it's not part of the horn coral itself, or is it?

Thanks to all for your input. 

 

Detail: 

 

[minnbuckeye]

Not part of the rugosa coral. But I don't think it is an epibiont ( an organism that lives on the surface of another organism) either. The "top" of the coral typically has a cone shaped depression. The unknown you are inquiring about sits too high to be attached to the coral as an epibiont. (Unless it extends deeper into the matrix)

 

 Mike

[Pippa]

Thanks for adding to my vocabulary, Mike!

 

So, an epibiont lives on top of its host, but differs from a (surface) parasite in that it doesn't live off it's host and therefore doesn't harm it.

The things I didn't know and never knew of and now I do...  :-) 

 

 

I agree, I don't think the "bump" had lived on the coral while it was alive.  While most (but not all) of my horn corals have a large depression on top, I think this horn coral too was hollow on top, but the depression had been filled with sediment by the time the "bump" grew there. 

So whatever it is, the term "buddy" is probably a be a bit of a stretch...

The question remains though: what is the bump?  Maybe a tiny solitary horn coral?

 

[Rockwood]

8 hours ago, Pippa said:

The question remains though: what is the bump?

I think bin mate might be a more accurate term than buddy. Eroded crinoid ossicle would seem a reasonable guess.

[westcoast]

Looks like a worn foraminiferan.

[Pippa]

6 hours ago, Rockwood said:

I think bin mate might be a more accurate term than buddy. Eroded crinoid ossicle would seem a reasonable guess.

Bin mate it is.

And probably a crinoid after all. 

Thanks, Rockwood! 

 

Oh, wait, wait, gotta look up foraminifera first....

[Pippa]

6 hours ago, westcoast said:

Looks like a worn foraminiferan.

Aha!  Another addition to my vocabulary.  

Off to google silurian foraminifera...

Thanks!

[Pippa]

 

6 hours ago, westcoast said: 

 

Looks like a worn foraminiferan.

 

Thanks for weighing in, @westcoast, I appreciate it.

I checked out the Illinois State Geological Survey  and very conveniently, they publish a plate of forams typically found in Illinois. I'm pretty sure the plate doesn't go into too much detail though. I assume that each name below, is the genus and the plate doesn't show the different species. Also, the size indicators next to each drawing are of no help, without knowing the dimensions of the printed plate. These creatures sure vary in size. Amazing!  

Do think any of those forams resemble my critter on the plate below? 

Maybe the psammosphaeran? The drawing doesn't show any of the visible details of my unknown "bump" though. No checkered edge for example.