Nanotyrannus or Dakotaraptor?

[Dino Dad 81]

Hey all,

 

 

What do you think of this one?

• Hell Creek formation, Powder River co, Montana
• CH: 10.9mm
• CBL: 6.6mm
• CBW: 2.9mm
• Mesial serration density: about 4.8/mm
• Distal serration density: about 4.0/mm
• Distal serrations are pretty worn except those near the tip, which look fairly chisel, but have an apical hook(?)

 

 

 

 

 

 

 

 

Thanks!

 

[hadrosauridae]

MEsial density doesnt seem high enough for DR, and also, IIRC DK has a "facet" appearance when you look at it from the side. I.E. its kinda like its 6-sided (hexaganal?) around the base.

 

So my guess is 

[Troodon]

Denticle alone shape says its a Tyrannosaurid

[Dino Dad 81]

@Troodon, regarding the denticles, is it anything worth noting that:

• both carinas seem to have a wide range in serration density--much denser towards the tip and base vs in the middle portion.
• the posterior serrations seem to hook apically towards the tip (see the last of the pictures posted above)

Are these reasonably within the tyrannosaur domain?

 

Thanks,

[Troodon]

Yep density changes are typical along the carinae on both edges of a large number of theropod teeth including T rex and other Tyrannosaurids.  Why I make point to measure in the middle to be consistent with published data.

  Not seeing an apical hook other that a few denticles have some slight tilt these are classic chisel shape denticles.  

You're obviously not satisfied with the tooths assignment and are fishing.  Isolated teeth are very difficult to ID especially ones that are so small.   If you compare the characteristics of this tooth to the two known Dromaeosaurids in the HC it does not fit.  I'm not going to create characteristics that are unknown.  If down the road more of these dentition is described or a new Dromaeosaurid is found we can have another look but right now it fits what I know as a Tyrannosaurid.

 

[Dino Dad 81]

No, not dissatisfied—nothing worse than a mid-ID—just trying to learn and those characteristics were part of what made me wonder if the tooth was unusual. Thanks as always, @Troodon !