Are these Juvenile Rexes?

[jikohr]

Hi everyone!

 

I acquired these two pretty recently and immediately though Juvenile Rex, but after that other one I figured I should be more careful and ask for a second opinion. Both are from the Hell Creek of Powder River County, Montana.

Tooth 1:

Crown Height: 11 mm

Crown Base Length: 5.5 mm

Crown Base Width: 5 mm

Mesial serration density: 4.5 per mm

Distal serration density: 4 per mm

Tooth 2:

Crown Height: 14 mm

Crown Base length: 7 mm

Crown Base Width: 5 mm

Mesial serration density: 4.5 per mm

Distal serration density: 3.25 per mm 

 

[Dino Dad 81]

First one seems more likely Rex to me. How confident are you in that mesial density?

Second one might be tyranno, but it might have a chance at a dromie premax/anterior (possibly Acheroraptor odd as that may sound).

[jikohr]

41 minutes ago, Dino Dad 81 said:

First one seems more likely Rex to me. How confident are you in that mesial density?

Second one might be tyranno, but it might have a chance at a dromie premax/anterior (possibly Acheroraptor odd as that may sound).

I am fully prepared for Bakker to come in and call them both Stegosaurus after that last one.

[jikohr]

Retook serration measurements on the second and got the same result.

[Troodon]

I would lean toward these teeth being Trex.  I say that because they are robust not what I would expect from Dromaeosaurids.  If you compare these teeth to the others we've discussed they are quite different.   Unfortunately we have very little to compare against to be certain.

[jikohr]

1 hour ago, Troodon said:

I would lean toward these teeth being Trex.  I say that because they are robust not what I would expect from Dromaeosaurids.  If you compare these teeth to the others we've discussed they are quite different.   Unfortunately we have very little to compare against to be certain.

Awesome!

Thanks man!

[Dino Dad 81]

@Troodon, the apparent DSDI on that second tooth (14mm) doesn't bother you with respect to tyrannosaur? When I zoom in and hold an object up to both sides, it looks like it could perhaps be 1.5+. I know it's tough when dealing with these little guys, but have you seen that DSDI can get higher on small tyranno teeth?

 

The other thing I was trying to account for in making sense of that one was tip wear, which seems like it could have the tooth looking quite a bit stockier than it originally was.

[Troodon]

What can I say, I certainly cannot definitely say T rex and don't, but they look like a smaller versions of big mama.  If the teeth were more slender it would be another story would be more like the dentition of Saurornitholestes.  Have no idea about DSDI its definitely a issue and concern.  Call it whatever you feel comfortable with since we have nothing published or to compare against.   We do not understand the dentition of the Dromaeosaurids  in the HC but we do know what Trex teeth dentary teeth look like.  

[jikohr]

1 hour ago, Troodon said:

What can I say, I certainly cannot definitely say T rex and don't, but they look like a smaller versions of big mama.  If the teeth were more slender it would be another story would be more like the dentition of Saurornitholestes.  Have no idea about DSDI its definitely a issue and concern.  Call it whatever you feel comfortable with since we have nothing published or to compare against.   We do not understand the dentition of the Dromaeosaurids  in the HC but we do know what Trex teeth dentary teeth look like.  

Fair enough. I'm putting an asterisk next to the weird one. Thanks for the input as always!