Stomach contents or not?

[Dinobot]

Hi all this may be a dumb question or too complex for a simple answer, but what factors determine if a bunch of fossils found in very very close proximity are actually the contents of a dinosaurs stomach? 

Thanks!

[LordTrilobite]

Well one thing that can make a difference is if there's evidence of acid etching on bone. If there's acid etching there's a higher chance it was eaten.

[Troodon]

Also, proximity is very important and if bones are present they would be broken fragments, probably not recognizable with very different preservation than the skeleton.  Ultra rare but the most common stomach content found are Gastroliths which are rounded stones found near the skeleton and different than other rocks in the surrounding area.

[Troodon]

Let me add you periodically see digested theropod teeth for sale.  Most are just poorly preserved ones.

[Dinobot]

4 hours ago, LordTrilobite said:

Well one thing that can make a difference is if there's evidence of acid etching on bone. If there's acid etching there's a higher chance it was eaten.

Ok thanks! what does acid etching on bone look like? 

[Dinobot]

3 hours ago, Troodon said:

Also, proximity is very important and if bones are present they would be broken fragments, probably not recognizable with very different preservation than the skeleton.  Ultra rare but the most common stomach content found are Gastroliths which are rounded stones found near the skeleton and different than other rocks in the surrounding area.

So if there are multiple unidentifiable bones in close proximity but there is not skeleton found surrounding it or near would it just be a bunch of bones?

[Troodon]

Well if the preservation of the bones look like the skeleton yes just a bunch of bones.  Also remember the theropod is going after the meat and any bones it ingest are fragments

[Dinobot]

Ok thanks!

[Dinobot]

1 hour ago, Troodon said:

Well if the preservation of the bones look like the skeleton yes just a bunch of bones.  Also remember the theropod is going after the meat and any bones it ingest are fragments

so I found this item for sale, and it looks to a  bunch of fragmented bones in close proximity, would this possibly be stomach contents? the seller said it was a partial dino rib, mammal toe and some other fragments pieces.  What would I be looking for in a piece like this to determine one way or another?

 

[Troodon]

I have a hard time seeing that larger bone would getting through its esophagus and into stomach.  Looks like a typical matrix block.  Bones look normal.

[aplomado]

Neat looking fossil, in any case!  I love matrix like that.

[Dinobot]

25 minutes ago, Troodon said:

I have a hard time seeing that larger bone would getting through its esophagus and into stomach.  Looks like a normal matrix block.  Bones look normal.

Ok thank you just didnt want to buy it and start taking it apart if it was possibly stomach contents!

[Dracarys]

Is it more likely to be section of a channel deposit where bones had collected? Can’t see this as stomach contents. 

[Dinobot]

1 hour ago, Dracarys said:

Is it more likely to be section of a channel deposit where bones had collected? Can’t see this as stomach contents. 

Hmm that makes sense 

[jpc]

1 hour ago, Dracarys said:

Is it more likely to be section of a channel deposit where bones had collected? Can’t see this as stomach contents. 

Exactly. These are quite common in the Lance and Hell Creek Formations.  Rather than being accumulated by being in a gut together these bones probably found their final resting spot thanks to Cretaceous river currents.   

[Dinobot]

Ok great thanks to you both!

[GeschWhat]

9 hours ago, Dinobot said:

Ok thanks! what does acid etching on bone look like? 

Here is a piece of what I think is acid etched bone from the Hell Creek Formation. When I was cleaning it up in the lab, I thought it was petrified wood until I put it under the microscope. Perhaps @Troodon and @jpc can confirm. 

[Dinobot]

3 hours ago, GeschWhat said:

Here is a piece of what I think is acid etched bone from the Hell Creek Formation. When I was cleaning it up in the lab, I thought it was petrified wood until I put it under the microscope. Perhaps @Troodon and @jpc can confirm. 

Thanks for the info and photo 

[Troodon]

9 hours ago, GeschWhat said:

Here is a piece of what I think is acid etched bone from the Hell Creek Formation. When I was cleaning it up in the lab, I thought it was petrified wood until I put it under the microscope. Perhaps @Troodon and @jpc can confirm. 

 

Certainly the right size and looks etched a good candidate

[jpc]

I can't tell if it is acid etched or just weathered from sitting on the Cretaceous ground for too long.  

[GeschWhat]

On 4/8/2020 at 1:09 PM, jpc said:

I can't tell if it is acid etched or just weathered from sitting on the Cretaceous ground for too long.  

Yeah, it was found in float material, so there is no way to know for sure.  

[jpc]

Lori... I do have a pile of little coprolites set aside to send you.  Be patient.