Skull Fragment with Ear Bone?

[Brandy Cole]

I had some spare time this week and have been going back through unidentified finds and sorting the ones where I think an ID may be possible.

 

Based on what I've learned, I think this may be a cranium section with ear bone visible.  But I can't figure out what animal it could be.  Any ideas are appreciated.

[Brandy Cole]

Adding a couple of ear close-ups.

 

[JohnJ]

It's a puzzle.  I cannot visualize a way this is part of a skull.  At the same time, the large interior cavities are hard place, too.  It seems the bone structure on the opposite, flatter eroded surface should have more of the cavernous skull structure, instead of the smaller, closed cell structure.  I'm wondering if this is part of the other end of an animal....  

 

It's probably something obvious that is slipping past my brain.  

[Brandy Cole]

@JohnJ

The flatness of it threw me too, which is one reason I just shoved it in a box.  But after learning more about ear bones, I noticed this looked like it may have one.

 

The only thought I had to explain the odd shape was possibly holmesina?

[JohnJ]

Maybe more angles of the overall shape will help?

[Brandy Cole]

Here are some other angle views.  Hopefully someone will have some ideas.  I'm really unsure how to orient it in photographs.

 

@Harry Pristis

@Shellseeker

@garyc

@GPayton

 

 

 

[Brandy Cole]

In the way I have the last photo oriented, the far right side has flat, intact cortical bone on the exterior, and the bottom has intact cortical bone running most of the length of the base.

[Harry Pristis]

I don't recognize the find.  My hunch is this is a fragment of long bone that has been excavated by an unknown invertebrate, perhaps clams.

[GPayton]

1 hour ago, Harry Pristis said:

I don't recognize the find.  My hunch is this is a fragment of long bone that has been excavated by an unknown invertebrate, perhaps clams.

I think I'd probably agree with Harry. My guess is that the large cavities are because this is a fragment of a long bone from a really large mammal, maybe mammoth, mastodon, sloth, or an especially large bison, which I think have the same air-filled cavities to keep their bones light that proboscidean skulls do. 

[JohnJ]

My first thought when I see a 90-ish degree angled cross section is consider a radius.  But, the cavities cause me problems with that suspicion.  

 

Still, I think the bone surface in the larger cavities looks like natural growth surface rather than an excavation into existing bone.  I see the 'ear' feature as a foramen for nerves or blood vessels.  So, I'm back to something 'skull adjacent'.  

 

Looking back at this mastodon skull model, I was noticing all the potential areas that might combine the features of your piece.  There may be a clues you can see in hand.

[Brandy Cole]

The holes to me do look much more consistent with natural morphology than burrows.  I think the skull model route is worth pursuing.  I was previously assuming this was a big piece of a relatively small skull.  I hadn't considered the possibility that it could be a small piece of a large skull. That could explain the very large cavities.

 

I'll see if anything seems to fit.  I may just lack enough defining features to come up with a positive ID.

[garyc]

It has a similar preservation to the tortoise material I find on the Brazos