T. rex or Nanotyrannus?

[-Andy-]

I know this won't help much but I am with Henry on this in that it is a tough call. The thickness of the tooth falls between Nano and Rex

 

As far as I am aware, Judith River Formation accounts for a small portion of the Garfield County > https://mrdata.usgs.gov/geology/state/fips-unit.php?code=f30033

 

Is there any way to be sure if this is from JRF or Hell Creek Formation?

[The_bro87]

I didn’t know that, but that’s really interesting that Garfield county has both formations. I just checked the original listing, and it said Hell creek formation in Garfield county. The more I look at the tooth, the more I’m starting to think it’s a rex tooth because the pinching is really hard to notice and it seems at least a little thicker proportionally than my other nano tooth. But then again that’s just one tooth, so I’m still not sure. I’ve been looking at teeth online and it really does look like it’s kind of in between 

[The_bro87]

Would it be helpful at all if I measured the length and width of the base and posted a picture of it with a scale? 

[-Andy-]

I think all forms of measurement would help

[The_bro87]

It was tougher to get a picture of the width with a scale, but the length is right around 9mm, and the width appears to be slightly under 5mm at it’s thickest. I apologize for the blurry photo of the width, I can take a new one if needed. 

[-Andy-]

On 12/29/2020 at 8:28 PM, The_bro87 said:

It was tougher to get a picture of the width with a scale, but the length is right around 9mm, and the width appears to be slightly under 5mm at it’s thickest. I apologize for the blurry photo of the width, I can take a new one if needed. 

 

 

I don't see much of a pinch here. If this is accurate, I would lean towards T. rex

[The_bro87]

I tried to get a clearer picture, in this one it looks slightly pinched on the left side, but not very much, and I can’t really tell if it’s on the right at all. JoeS and hxmendoz said that this might not rule out rex, which I thought was really interesting since I always thought that feature was only in Nanotyrannus teeth. Looking at the tooth in person, it’s hard to see the pinch on the right but it is still noticeable, but doesn’t appear very concave in at all when looking at the side of the tooth like on other nano teeth. 

[Troodon]

I would assign this tooth most likely to be a maxillary of Trex given the width and height proportions and shape of base.   Denticles also appear to travel across the apex typical trex.  I've found that density counts on small tyrannosaurid teeth are not a good characteristic to use as an ID. 

[The_bro87]

Thank you all again so much for the help, this is a really interesting tooth and I feel like I’ve learned a lot from the forum over this tooth. I’m going to label it T. Rex in my collection but I’ll still check and see if anyone else has ideas about the tooth on this post. This is definitely one of the cooler teeth in my collection, and I’m happy to have an Id now