Hell Creek Tooth Identification / Antemortem Enamel Spalling

[Joseph Kapler]

This partial crown was collected from the Hell Creek Formation, Garfield County, Montana. I acquired it for a teaching collection because I think it tells a story. The basal section shows almost an inch in diameter.  Is this a Trex tooth?  The tooth shows antemortem enamel spalling and wear as described by Schupert and  Ungar, 2005.  It feels as though that the tooth was broken as a result of probably bone crushing and was worn smooth with continued feeding, then shed some time later. 

 

I would appreciate your thoughts.

[Troodon]

Yes its a T rex fragment

[Joseph Kapler]

Super! Given the base dimensions would this be considered an adult tooth -- any estimate on how long the tooth might have been or functional morphology?  Do you agree with the notion of antemortem breaking and wear?

[Dino Dad 81]

I love story-tellers like that! Very cool tooth @Joseph Kapler

 

You might be lucky with regard to how much can be determined from what you've got. I've tried to learn some about heterodonty in T Rex, so I'll take a stab here at using Heterodonty in Tyrannosaurus rex implications for the taxonomic and systematic utility of theropod dentitions, but Troodon can let us know if I'm off.

 

With CBL of 50.1mm and CBW of 43.6mm, the size appears to be large adult (first page below tables A and B).

 

Your CBR of .87 is so high that you may even be able to conclude it's a Maxillary 9 or Dentary 9 (second page below table A scatter plot). So it may be a tooth (either top or bottom) that's about 75% of the way towards the back of the mouth. And that's also assuming Troodon thinks you measured CBL and CBW accurately.

 

So now the following is out of my league, but I'll tell you what I imagine the story of your tooth is. Your T Rex bites off chunks off meat and bone and raises its head to do whatever chewing is necessary using the back of the mouth, which is where your tooth is positioned. Perhaps those amazing wear facets reflect it having had to do a heavy amount of the bone crunching.

[Troodon]

 It's possible that it's antemortem spalling, you do seem to have a good candidate for that but it's a guess.  The tooth looks like it's from a dentary position most likely from an adult but tooth size in not a primary indicator of age.   We can try to compare it to known ones like Dino Dad did but I prefer looking at where the carinae are located.  So can you also point out where the carinae are located in that base photo.

Can you also verify the base dimensions, need to be taken where shown in the illustration below.  Not sure how best to read your numbers on the base photo.

 

[Joseph Kapler]

In the basal section, the CBL and carina are pretty close as shown by the 50.1 mm measurement.  It follows the orientation of the depression in the core of the tooth and favors the top half of the tooth as shown.

[Dino Dad 81]

Based on this pic:

 

I suspect my red circles are pretty close:

 

[Joseph Kapler]

I will redo the measurements using your picks and repost.  Thanks.

[Joseph Kapler]