Willow Creek Formation - Hadrosaur Indent

[svcgoat]

So I was reading up on the Willow Creek Formation and noticed that only three species have been found there. T. Rex, Montanoceratops and Hadrosauridae indet. 

 

My question is if its the same geological time period as Hell Creek formation what diagnostics are they missing to say thats its Edmontosaurus as that was the only Hadrosaur in HC?

 

I guess what I really want to know is how are Hadrosaurs most usually classified? Is it Skull material or is a mostly complete specimen required?

[Troodon]

 I know nothing about this unit but obviously there is not enough material discovered to point to a specific genus.   Whoever is doing the research has to feel comfortable that they can make a call.  We know quite a lot about Edmontosaurus so skull elements or bones that compare well might be enough.  You cannot call it a specific genus unless you can draw those comparisons.   You cannot assume its an Edmonto without evidence

 

[svcgoat]

6 minutes ago, Troodon said:

 I know nothing about this unit but obviously there is not enough material discovered to point to a specific genus.   Whoever is doing the research has to feel comfortable that they can make a call.  We know quite a lot about Edmontosaurus so skull elements or bones that compare well might be enough.  You cannot call it a specific genus unless you can draw those comparisons.   You cannot assume its an Edmonto without evidence

 

That's what I thought. I was also wondering what elements of hadrosaur skeleton most often lead to identification 

[Troodon]

You should ask D. Evans what skull elements he would be confortable seeing to make that call, every paleontologist may be different.  Elements like the jaws, jugal,  quadrate may be sufficient for them since they can be diagnostic.  Just one may be sufficient.  Also more diagnostic bones like the humerus or femur might surfice.  You dont need a skeleton to say its an Edmonto just a good comparative element.

[svcgoat]

16 hours ago, Troodon said:

You should ask D. Evans what skull elements he would be confortable seeing to make that call, every paleontologist may be different.  Elements like the jaws, jugal,  quadrate may be sufficient for them since they can be diagnostic.  Just one may be sufficient.  Also more diagnostic bones like the humerus or femur might surfice.  You dont need a skeleton to say its an Edmonto just a good comparative element.

Thank you