Theropod Bone

[Pterosaur]

Hi everyone, 

 

I have another bone I would love for you to identify if you can. I also found this one in Montana. It's definitely hollow and theropod. It looks like it has some kind of process along the side. It's not a concretion. 

 

What's really neat about the bone is that you can still see the struts inside. From what I understand, struts are structures found within pneumatic bones that allowed the bone to be lightweight while also creating pockets of air within the bone (air sacs) which essentially aided in respiration. (Please correct me if I'm wrong  ). Birds still have these struts today; which is pretty incredible to think about... 

 

Anyways, please let me know what you think this might come from! It's medium sized. Just over 8 inches long. 

 

Thank you!!

-Lauren 

[jpc]

I think you are right.  Pretty delicate as theropods go. Possibly Ornithomimid.  

[FossilDudeCO]

I would agree with ornithomimid too.

I am no expert, but seems similar to the very few I have seen.

[Pterosaur]

3 minutes ago, jpc said:

I think you are right.  Pretty delicate as theropods go. Possibly Ornithomimid.  

 

1 minute ago, FossilDudeCO said:

I would agree with ornithomimid too.

I am no expert, but seems similar to the very few I have seen.

 

Thank you! Any idea what bone it may be? Maybe an arm bone?

[PFOOLEY]

I just learned the defenition of pneumatized...excellent tag.  

[jpc]

My guess is femur.  It can be tough to ID for sure without ends.  

[Ridgehiker]

35 minutes ago, jpc said:

My guess is femur.  It can be tough to ID for sure without ends.  

 

Some type of theropod.

 

From the size I would agree with JPC and also guess an ornithomimid femur. It seems the right diameter and thickness. But, without the ends, just a guess.

 

The other possibility is some type of tyrannosaur metatarsal/metacarpal but the shape is a bit too twisty. Also these elements tend to be a bit flat on one side.  

[FossilDudeCO]

If you Google Image search Struthomimus femur.

It is fairly close!

The seemingly large curve to your bone was throwing me, but I think ornithomimid femur is as good as we will get!

[Susan from PA]

Hi Lauren,

Was this collected in the same area as your Trike horn? .  

 

Just an to play devil's advocate.  Here are two femurs from my collection.  The first femur has been identified as Nanotyrannus by Neal Larson who prepared the specimen.  It is 19th inches in length, and was found in the same area as your Trike horn.  There is quite a curve to the shaft.  

 

The next image is of my Strutiomimus femur.  Even though it is from the opposite side, you can see that there is not much curvature to the shaft.  This femur was collected in Hell Creek Formation, Harding County, South Dakota.  It is a rather large femur at 24 inches in length.  Hope this helps! . 

 

Here is a photo of the Strutiomimus femur from BHI. 

 

[FossilDudeCO]

Thanks for sharing Susan!

you aren't helping, but I cant argue with pictures!

[Susan from PA]

5 minutes ago, FossilDudeCO said:

Thanks for sharing Susan!

you aren't helping, but I cant argue with pictures!

Sorry Blake!  I thought I would stir the pot a little! .  

[FossilDudeCO]

@Susan from PA

Please do!

I am getting good with my Pleistocene mammals, my dinos need lots more work!

[Pterosaur]

3 hours ago, Susan from PA said:

Hi Lauren,

Was this collected in the same area as your Trike horn? .  

 

Just an to play devil's advocate.  Here are two femurs from my collection.  The first femur has been identified as Nanotyrannus by Neal Larson who prepared the specimen.  It is 19th inches in length, and was found in the same area as your Trike horn.  There is quite a curve to the shaft.  

 

The next image is of my Strutiomimus femur.  Even though it is from the opposite side, you can see that there is not much curvature to the shaft.  This femur was collected in Hell Creek Formation, Harding County, South Dakota.  It is a rather large femur at 24 inches in length.  Hope this helps! . 

 

Here is a photo of the Strutiomimus femur from BHI. 

 

 

Hey Susan! Thanks for sharing the great pictures! The bone is actually really curved and fits the shape of the nano femur you posted. It's crazy but I do think this is a femur of some kind. It seems a fair bit shorter than either of yours though. It also has a weird, beat up process on the side that is definitely bone. 

[Pterosaur]

9 hours ago, Canadawest said:

 

Some type of theropod.

 

From the size I would agree with JPC and also guess an ornithomimid femur. It seems the right diameter and thickness. But, without the ends, just a guess.

 

The other possibility is some type of tyrannosaur metatarsal/metacarpal but the shape is a bit too twisty. Also these elements tend to be a bit flat on one side.  

 

5 hours ago, FossilDudeCO said:

If you Google Image search Struthomimus femur.

It is fairly close!

The seemingly large curve to your bone was throwing me, but I think ornithomimid femur is as good as we will get!

 

Geez. The suggestions you all are coming up with are really interesting.. i know it's frustrating but I LOVE fossil puzzles like this. It makes the bone so intriguing and I find myself picking them up to think about them all the time and visually comparing them to dinos at the museum when I go.. lol