Didymoceras ammonite identification

[Mochaccino]

Hello,

 

Can someone help me identify these two Didymoceras pieces to the species-level? They are from Montana and both were repaired from a few fragments, though neither is said to be composite. From what I can tell they are in the 10-15cm range in terms of size.

 

1. This one seems to be part of the inner whorl, and based on how close the coil is I think D. cheyennense might be excluded, which leaves either D. stevensoni or D. nebrascense?

 

Also in the 3rd photo there is a strange mismatch between the fragments...a poor fit or composite perhaps?

 

 

2. This looks like a section of the inner whorl lower closer to the living chamber.

 

Any help would be appreciated, thanks!

 

[jpc]

Nice pieces.  Yup, Didymoceras, but I am not smart enough to tell you which species.  As for the break (?) in the third photo.  Tough to call, but I have seen some of these with natural micro-faults going through them just like this.  

[Mochaccino]

9 hours ago, jpc said:

Nice pieces.  Yup, Didymoceras, but I am not smart enough to tell you which species.  As for the break (?) in the third photo.  Tough to call, but I have seen some of these with natural micro-faults going through them just like this.  

True, actually now that I take a closer look,  in the second photo this segment looks to be joined very unnaturally. The junction is very odd and the change in angle of coiling seems unnaturally abrupt. I suspect this piece does not quite fit here...