Shark Barf?

[Jimbone]

Thoughts on these Mosasaur caudal vertebrae being shark eaten, partially digested and regurgitated? Images from http://oceansofkansas.com/mosapath.html seem to support this. Thanks, Jim

[JohnJ]

Some context information would be useful.  Were they found associated, separately, geologic formation, etc.  

[Jimbone]

Yes, of course, they were found in the Republican river valley of south central Nebraska. These were found together and fit together nicely. Found below an eroding layer of Pierre shale after a heavy rain.

[JohnJ]

In my experience, some formations can vary widely in how bone is preserved.  The minerals present can affect the chemistry in the rock...often, 'eating' away bone surface. 

 

If there are places like that in the Pierre Shale, it may be hard to differentiate between those eroded by stomach acids or acidic matrix.

 

@jpc

[Jimbone]

Thanks, that makes sense, I found a gov paper (here) on the Pierre shale though broad, it showed mostly neutral and if unweathered  it was less acidic. Calcite is also present in the shale but I read is only slightly acidic. I think a PH test on the surrounding matrix at the location will be a helpful data point. Also, these vertebrae found a few miles away in Pierre shale are in much better condition. 

 

Jim 

[Fin Lover]

How would you differentiate between ones that were regurgitated and ones that...made it all the way through the digestive system?

[Rockwood]

2 hours ago, Fin Lover said:

How would you differentiate between ones that were regurgitated and ones that...made it all the way through the digestive system?

Size would have to be a factor.

[Mark Kmiecik]

"Slightly" acidic shale over thousands of years can have a dramatic effect.

[jpc]

bones from the Pierre Shale are notoriously badly preserved.  No need to have them be vomitted or digested.  Just bad preservation.  There are exceptions, of course.  But these look like regular ole Pierre Shale mosasaur verts.  Great find nonetheless.  Esp for Nebraska.