Unknown fossil Montana

[bcfossilcollector]

[bcfossilcollector]

Hi. Forgot to include text. This particular fossil bone was found in Montana near the Alberta border in depositions that are Cretaceous in age. Bone measures about 6 inches in length. Thought to be dinosaur but I really do not know as regards this specimen. @Troodon @jpc

[bcfossilcollector]

[Troodon]

Its a rib from a Champsosaurus

[bcfossilcollector]

@Troodon thanks for the id. I suspected it wasn’t dinosaur. Much appreciated. 

[Pemphix]

Nice bone, i like it !

[Rockwood]

That's a who da thunk it !

[Mark Kmiecik]

17 hours ago, Troodon said:

Its a rib from a Champsosaurus

What are the defining characteristics? I'm not questioning the ID, just trying to understand what makes it Champosaurus. (I'm clueless beyond 'It's a bone'.)

[Troodon]

32 minutes ago, Mark Kmiecik said:

What are the defining characteristics? I'm not questioning the ID, just trying to understand what makes it Champosaurus. (I'm clueless beyond 'It's a bone'.)

Its not Champosaurus but Champsosaurus.  Champsosaurus material is found routinely in the Hell Creek Fm so Im pretty familar with lots of its bones even though this one from a different fauna.    I do have literature that initially helped me understand and identify its bones.  Ribs of this critter have a slight curvature with squared off ends.  

 

7 & 8 are dorsal ribs.

[Mark Kmiecik]

So it's primarily frequent exposure after you do the initial research, I guess? I suppose it also helps to be familiar with the site in question.

 

I'm always impressed by how some people can just look at a bone and identify it almost immediately. I think it will take me some time yet before I can see the subtle differences among them. I can usually tell which bone it is, but not the animal it's from. Trying to shorten my learning curve.

[jpc]

I'm glad troodon got to this one before I did.  We get so few champsosur bones other than verts in WY, that I am quite unfamiliar with them.  Yes, Mark, frequent exposure is the best.  I do have a few, but they are form MT, not WY.