This lovely oddity needs an ID

[DeepTimeIsotopes]

 

[DeepTimeIsotopes]

Found in the Mancos Shale in the San Rafael Swell, Utah. Late Cretaceous in age. Found in conjunction with several ammonites.

[DeepTimeIsotopes]

[JohnJ]

Possibly the keel imprint from a local ammonite.

[TqB]

3 minutes ago, JohnJ said:

Possibly the keel imprint from a local ammonite.

My first thought too.

[The Amateur Paleontologist]

My first thought was "trilobite pygidium", to be honest - then I saw you wrote 'Late Cretaceous'  

-Christian

[DeepTimeIsotopes]

34 minutes ago, The Amateur Paleontologist said:

My first thought was "trilobite pygidium", to be honest - then I saw you wrote 'Late Cretaceous'  

-Christian

It is most definitely Late Cretaceous. There's no paleozoic rocks for 100 miles near the location I got this.

[DeepTimeIsotopes]

3 hours ago, JohnJ said:

Possibly the keel imprint from a local ammonite.

My friend has an identical one. I don't have pictures of his unfortunately. 

 

Just kidding, his is different.

Edited December 7, 2018 by UtahFossilHunter

[DPS Ammonite]

Clam? Plant?

 

Most ornamentation/ribs on Cretaceous ammonites that I have seen are roughly at a right angle to the keel. The ribs in photos are at a very acute angle to the suggested keel. Can anyone provide pictures of ammonites with ribs at a similar angle?

[DeepTimeIsotopes]

41 minutes ago, DPS Ammonite said:

Clam? Plant?

 

Most ornamentation/ribs on Cretaceous ammonites that I have seen are roughly at a right angle to the keel. The ribs in photos are at a very acute angle to the suggested keel. Can anyone provide pictures of ammonites with ribs at a similar angle?

I think it may be this one...?

[Bronzviking]

At first glance it looks like a leaf imprint (external mold). Really cool find!

I found this picture that looks similar. What about a Pygidia of Pseudophillipsia sp.; (a) internal mould 

https://www.researchgate.net/figure/Pygidia-of-three-Middle-Permian-species-of-Pseudophillipsia-compared-to-the-Malaysian_fig4_225780237

[DeepTimeIsotopes]

18 hours ago, Bronzviking said:

At first glance it looks like a leaf imprint (external mold). Really cool find!

I found this picture that looks similar. What about a Pygidia of Pseudophillipsia sp.; (a) internal mould 

https://www.researchgate.net/figure/Pygidia-of-three-Middle-Permian-species-of-Pseudophillipsia-compared-to-the-Malaysian_fig4_225780237

 

That looks very similar to what I’ve got but the Mancos Shale is late Cretaceous in age. If it were a trilobite pygidium, I’d be a lot more excited because that would be Nature-paper worthy!

Edited December 8, 2018 by UtahFossilHunter
Removed pic