Cambrian Coralomorphs in the BAS in Arizona

[Arizona Chris]

Hi all,

 

Here is the LAST report on the truly amazing fossils we have found at the SW (Stevens Way, Ashfork) locality in the Bright Angel Shale, far south of the Grand Canyon.  These were listed by us for years as "problematica" or "mystery sponges" and since then, a coordinated effort by the members of the museum (Mesa) and a bit of direction on the literature by Piranha here at this forum has illuminated the dark path to identifying these elusive animals.  Never heard of a "Coralomorph"?  Neither did we up until this past few months.  In fact, we found many Cambrian researchers had not either.  I am posting this here so all can see and enjoy yet another amazing Cambrian animal most of us have been unaware of.  Only a few localities exist in the US, and a handful in the entire world. 

 

First, we have produced a extensive graphics filled write up on my web site here:

http://www.schursastrophotography.com/paleo/Fossilfotos-4h.html

 

However, Ill post a few images from this write up here to whet your interest!

 

General field appearance in the green shales on the surface of a coralomorph at 10x:

 

Side view of a fragment of the vase shaped animal laying on its side:

 

20x view of another surface impression.  The bundles of tubes go down into the shale layers several centimeters.

 

 

10x side view with calices visible.  Coralomorphs are very similar in appearance to a very primitive tabulate coral.  But 10x smaller and they have to partitions in the tubes.

 

The fragments are radial pieces of the compete animal.  Our first reconstruction of the complete fragments looked like this:

 

Finally, my attempt to show what the animal would have looked like in its live state.  They were about the size of a tennis ball for our specimens.

 

Again - Take look at our write up and there are many more images, graphics and information on how we found and finally identified these enigmatic animals.

 

http://www.schursastrophotography.com/paleo/Fossilfotos-4h.html

[izak_]

Fantastic job! 

But... I would've just gone with trilobite eggs  

[ynot]

Nice!

Thanks for sharing it here.

[Arizona Chris]

I saw those trilobite eggs at the Tucson show this year, totally amazing.  They had a microscope set up and you could look at the pyritized trilobites with hairs on thier legs.  The eggs were stuck underneath the cephalon, what a strange place to put them.

[izak_]

56 minutes ago, Arizona Chris said:

I saw those trilobite eggs at the Tucson show this year, totally amazing.  They had a microscope set up and you could look at the pyritized trilobites with hairs on thier legs.  The eggs were stuck underneath the cephalon, what a strange place to put them.

Awesome! 

[piranha]

15 hours ago, Arizona Chris said:

...The eggs were stuck underneath the cephalon, what a strange place to put them.

 

 

Actually, not so strange:

 

Quote:

 

"The location of the eggs is consistent with where modern female horseshoe crabs release their unfertilized eggs from the ovarian network within their head."

 

Hegna, T.A., Martin, M.J., & Darroch, S.A.F. (2017)

Pyritized in situ trilobite eggs from the Ordovician of New York (Lorraine Group): Implications for trilobite reproductive biology.

Geological Society of America, Geology, 45(3):199-202  PDF LINK