Hell Creek cervical rib?

[ThePhysicist]

Hi y'all. I bought a lot of fragmentary, unidentified dinosaur rib bones from Hell Creek, Harding Co., SD. I didn't buy them for this bone in particular, but once in-hand, it caught my eye and I wondered if it was identifiable since it had a more unique shape. This of course may be wishful thinking, and I'm fine with it remaining unidentifiable.

 

 

My primary guess is it being the proximal end of a Tyrannosaur cervical rib. I referenced Brochu (2002) "Osteology of Tyrannosaurus rex: Insights from a Nearly Complete Skeleton and High- Resolution Computed Tomographic Analysis of the Skull." 

 

^scale bar is 15 cm

 

It seems very similar, in my eyes. It has the right size and form on both sides of the rib. However, I don't know if Tyrannosaur cervical ribs are similar to those of other dinosaurs in Hell Creek, so it could still be unident. Or, my lack of knowledge could be unreasonably stretching the resemblance.

[hadrosauridae]

Tough call.  You've certainly done your homework and presented a good possibility.  I know that Hadrosaur ribs also have that same "wing" structure on the proximal end of ribs.  ITs hard to tell from a picture of a fragment (at least for me) .  I know all the theropod material I have handled has a very different look and feel in person, but since yours looks to be weathered float, its also obscuring some of the characteristics.

[ThePhysicist]

On 4/23/2021 at 10:28 PM, hadrosauridae said:

its also obscuring some of the characteristics

what are some of these characteristics that you're looking for?

 

@Troodon, @jpc, @LordTrilobite, any thoughts?

[hadrosauridae]

1 hour ago, ThePhysicist said:

what are some of these characteristics that you're looking for?

 

 

 

The theropod material I handled is 1, denser and heavier, 2 typically very dark in outer color, 3 often smoother, denser, shinier in appearance.  ITs kinda hard to explain but easier to see in person after comparing herbivore and carnivore side by side. 

 

And I'm sure my observations are far from universal for the Hell Creek.

[jpc]

Yes on rib frag.  You have done some good homework there, but I don't think it is a rex rib.  For me, without seeing it in person, I cannot say.  And even if I had it in my hand, I don't know if there is ennough of it to say which critter of which part of the body.  Off hand, it looks too bulky for a neck rib.  

[Troodon]

I have a hard enough time with identification of complete ribs, small fragments are rough because of the similarity between them.   I've added a picture of an Edmontosaurus regalis rib set,  the first one is a cervical long rib all the others cervical are short.  I dont think yours is one from all the ones Ive dug up, too much curvature.

 

A feature that might say theropod is that the bone looks a bit pneumatic with a honeycomb structure in your third photo.  

 

[LordTrilobite]

I'd say indeterminate dorsal rib. It's a nice curve but other than that it doesn't have much in terms of identifiable features. Seems more likely to be a large herbivore just because they are more common.