Another Weird Hell Creek Tooth id Nanotyrannus? Dromaeosaur?

[jikohr]

Hi everyone!

 

Here's another little tooth that has me stumped. It has a pinch like a Nano, but the serration density is what I've come to expect from a raptor.
At least I got some really nice shots of the serrations!

CH: 8 mm

CBL: 5.5 mm

CBW: 2 mm

mesial serration density: 6/mm

distal serration density: 4.25/mm

So what do you all think? Nano? Dakotaraptor? Tyrannosaur/Dromaeosaur indet.?

Any insight is appreciated as always!

 

Edited April 6, 2022 by jikohr
rearrange photos

[Nanotyrannus35]

Looks like dromaeosaur to me. Base and tooth shape seem different from nano.

[jikohr]

That was what I thought also at first, but I just want to make sure. Honestly I'm kinda leaning toward Dakotaraptor on it but I'm really hesitant to label anything that. I got one a week ago. I'll be shocked if this is another one.

[Troodon]

This one is difficult and its small size does not help.  The shape of the denticles and slight mesial twist says Tyrannosaurid while a strong DSDI says Dromaeosaurid.   I dont believe its Dakotaraptor or Acherorapter since a number of characteristics dont work.    

 

I believe there is a good chance there is another Dromaeosaurid in the HC so it might be that.

 

Can you recheck density.

[jikohr]

5 minutes ago, Troodon said:

This one is difficult and its small size does not help.  The shape of the denticles and slight mesial twist says Tyrannosaurid while a strong DSDI says Dromaeosaurid.   I dont believe its Dakotaraptor or Acherorapter since a number of characteristics dont work.    

 

I believe there is a good chance there is another Dromaeosaurid in the HC so it might be that.

 

Can you recheck density.

Really? Wow, I'm really glad I'm checking! Here's some pics with the serrations next to a mm scale bar. I'll go retake measurements from scratch and get another pic of the mesial carina since the "twist" might be a bit exaggerated in that photo.

[Troodon]

My vote is that its a Tyrannosaurid based on shape and density of denticles

[jikohr]

Just now, Troodon said:

My vote is that its a Tyrannosaurid

Tyrannosaur indet.?

[Troodon]

Yes

[jikohr]

Just now, Troodon said:

Yes

Tyrannosaur indet. it is then!

Thanks man!

[jikohr]

57 minutes ago, Troodon said:

This one is difficult and its small size does not help.  The shape of the denticles and slight mesial twist says Tyrannosaurid while a strong DSDI says Dromaeosaurid.   I dont believe its Dakotaraptor or Acherorapter since a number of characteristics dont work.    

 

I believe there is a good chance there is another Dromaeosaurid in the HC so it might be that.

 

Can you recheck density.

Oh by the way, I rechecked the serration density and found distal serration density of 5/mm at about 1 mm lower down then where I originally measured.

[Dino Dad 81]

I'm surprised the base pinch wasn't a bigger driver of the Tyrannosaurid thinking. It's minor here, but any degree of it typically rules out DR and suggests nano.

[Troodon]

Your tooth got me interested so I checked my collection to see if I had something similar and found a couple.    Here is one that is in pretty good shape, a bit smaller, but extremely similar.  I'm still leaning toward Nano because of the denticle shape but would not rule out an indeterminate Dromaeosaurid.   The base has a pinch, and its shape, non-rectangular, might just be a function of an immature tooth but don't know.   The CHR and denticle shape do not compare well with Dakotaraptor.   Hard to diagnose teeth this small since we don't know what ontogenetic changes occur other than density.

 

  I've had discussions with Pete Larsen about a 3rd Dromaeosaurid in the HC, so I do plan on showing him this tooth.

 

 

[jikohr]

2 hours ago, Troodon said:

Your tooth got me interested so I checked my collection to see if I had something similar and found a couple.    Here is one that is in pretty good shape, a bit smaller, but extremely similar.  I'm still leaning toward Nano because of the denticle shape but would not rule out an indeterminate Dromaeosaurid.   The base has a pinch, and its shape, non-rectangular, might just be a function of an immature tooth but don't know.   The CHR and denticle shape do not compare well with Dakotaraptor.   Hard to diagnose teeth this small since we don't know what ontogenetic changes occur other than density.

 

  I've had discussions with Pete Larsen about a 3rd Dromaeosaurid in the HC, so I do plan on showing him this tooth.

 

 

I haven't done a serration count on this one, but I do have another tiny one that is a Nano if that helps. Complete with rectangular pinched base and a mesial carinae that veers of to the side. I can supply some more data in a little bit, I'm helping my family pack up for a big vacation right now, but anything I can do to help especially if it might be a new discovery!

[Troodon]

Thanks, I need to talk to Pete about the shape of these bases.  Not typical of what is understood for Nano but yours is clearly one.  Again might be ontogenetic.