Arizona Pennsylvanian Coral

[DPS Ammonite]

The corals from the Pennsylvanian Naco Formation in Arizona have not been officially described partly because many are silicified and have lost internal details. Any idea what these corals are with central columns that are vertically striated? Their average length is 2 to 3 cm. I think that they look like Lophophyllidium.

 

Thanks,

John

[BobWill]

I was told to label the similar looking ones from Texas as Lophophyllidium proliferum. I heard that to be sure you need to have a look inside for other details. I'll ask Dr. Ben Neuman his opinion since he has been having a closer look at these. He is cutting into some for a look at some feature he identified as helpful.

[Herb]

I agree with Bob Will

[Missourian]

All these silicified fossils are fascinating.

 

Is the matrix limestone? If so, have you tried dissolving some in acid? I've had luck doing so with HCl/muriatic. See:

 

http://www.thefossilforum.com/index.php?/topic/30498-some-pennsylvanian-gastropods/&

and

http://www.thefossilforum.com/index.php?/topic/33865-adventures-in-microscopy/&do=findComment&comment=377885

[BobWill]

I got this email reply from Dr. Neuman. I'm trying to coax him into joining the forum:

 

Corals are tough, and like you said on the forum, there will need to be some sectioning to know for sure.  These look pretty well preserved - I bet they have plenty of detail inside.

 

Most likely these belong somewhere in Lophophyllidium.  L. proliferum is Missourian and so far only certainly from Illinois, though it may have spread.  I read somewhere that this formation is probably Desmoinesian - does that sound right?  If so, we need to compare to some of the earlier species.

 

There may be up to three species there - the bottom two seem similar but different from the top one, and the one that is on its side at the back is probably different based on looking more cylindrical, if I am seeing it correctly.  

 

Need to see more pictures of them all lined up in side view, or all with the tips stuck into something so we can see right down the cup, if he can do that.

 

We also need a measurement - what is the diameter at the top?  Diameter per number of septa is helpful in separating them.

 

My guess for the bottom two is something like L. newelli.  The top one is tougher since it is missing the top of the cup, and not sure about the one that is sideways.  

 

If the original poster has a decent number of non-precious specimens, it would be fun to section them and find out who they are.

 

Benjamin Neuman

 

Chair of Biological Sciences

STEM 318G

Texas A&M University-Texarkana