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Identification Tyrannosaurid Teeth From Canada & United States


Troodon

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17 minutes ago, Omnomosaurus said:

 

That's a good point actually. The terminology might just confuse matters more for people, especially when things like DSDI calculations already look scary enough if you're not familiar with them. Probably best to leave it out; especially with the ambiguity of the statements too.

 

I'll add the query on this to the list for Christophe... there'll be a novel for him before long, if the questions keep coming at this rate!

I agree just the other day I was having problems with the DSDI, probably will be very confusing to the other members.

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22 minutes ago, dinosaur man said:

I agree just the other day I was having problems with the DSDI, probably will be very confusing to the other members.

 

Yeah, it took me time to wrap my head around it in the beginning too, since it seems pretty difficult to find resources that actually break down the basic method of how to calculate these sorts of things. That's one thing the forums are amazing for.

 

 

As this process concerns analysing denticles, I'll post the extremely fine serrations of my indet. tooth from Dinosaur Provincial Park for visual reference to others.

 

Distal Carina (9/5mm)

1578316997151.jpg.5bccd0b8640b505ea3a94f6519836628.jpg

 

Mesial Carina (19/5mm)

1578317060149.jpg.42d6fe160f67fecd5b600c6e5af5951f.jpg

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1 hour ago, Omnomosaurus said:

I'll add the query on this to the list for Christophe... there'll be a novel for him before long, if the questions keep coming at this rate!

I actually think he would appreciate the technical questions you'll ask him.  Shows you've studied his paper, have questions and are not just looking to get an ID .  Also eager to hear what he says about your tooth.  His method says Daspletosaurus lets see if he agrees 

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1 hour ago, Troodon said:

I actually think he would appreciate the technical questions you'll ask him.  Shows you've studied his paper, have questions and are not just looking to get an ID .  Also eager to hear what he says about your tooth.  His method says Daspletosaurus lets see if he agrees 

 

Yeah, I guess he might appreciate some technical queries....If I get chance in the next couple of days, I'll put together an email to him covering the main questions we've raised around this method.

 

I'm interested to find out too, and hope he agrees with the Daspletosaurus ID, or its going to muddy the waters even more for us trying to ID other teeth!

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  • 7 months later...

I've recently had a little chat with Phil Currie around Tyrannosaurid teeth, and he mentioned the subject of enamel "crinkling".

 

Phil wasn't aware of any publication on the feature, but Jim Farlow apparently made the observation years ago that crinkling of the tooth enamel is a feature found solely on tyrannosaurine teeth, and is not present in those of the albertosaurinae.

 

Approx. 25% of tyrannosaurine teeth have enamel crinkles, but Phil is confident that the presence of them can be used as a diagnostic tool to confidently rule out the possibility of it belonging to an albertosaurine tyrannosaur.

 

A tooth lacking this enamel ornamentation can still belong to either the tyrannosaurine or albertosaurinae however.

 

Might be another useful diagnostic tool for a small portion of those Gorgosaurus/Daspletosaurus contenders.

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On 9/4/2020 at 2:47 PM, Omnomosaurus said:

I've recently had a little chat with Phil Currie around Tyrannosaurid teeth, and he mentioned the subject of enamel "crinkling".

 

Phil wasn't aware of any publication on the feature, but Jim Farlow apparently made the observation years ago that crinkling of the tooth enamel is a feature found solely on tyrannosaurine teeth, and is not present in those of the albertosaurinae.

 

Approx. 25% of tyrannosaurine teeth have enamel crinkles, but Phil is confident that the presence of them can be used as a diagnostic tool to confidently rule out the possibility of it belonging to an albertosaurine tyrannosaur.

 

A tooth lacking this enamel ornamentation can still belong to either the tyrannosaurine or albertosaurinae however.

 

Might be another useful diagnostic tool for a small portion of those Gorgosaurus/Daspletosaurus contenders.

He told me the same thing, it’s interesting, especially why they had these!

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Here is a skull from the Judith River Formation that is being called Daspletosaurus and I'm sure a paper will follow.  Dr. Fowler just posted this update on a skull and indicated that they have 4 tyrannosaurid projects that include an articulated skeleton.   Denver was non-committal on the species and said its being studied but all projects were from the same unit so most likely the same species.  

 

 

Dalpleto.thumb.jpg.fe707ab0c9b1b604ff2b9f9dca356442.jpg

 

Jaws are being prepped.. awesome looking

 

Dalpleto2.thumb.jpg.9b3137e853cc0c20a4cb0521283a714d.jpg

EeyRZaeXgAI_Ist.jpg.fe1d2ae0ac2e2e4f352a823e2320bdce.jpg

 

Nice preservation on postorbital

Dalpleto3.thumb.jpg.92869571003e58b64ee8a03cfe919a63.jpg

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  • 2 months later...
  • Troodon changed the title to Can You Identify Tyrannosaurid Teeth From North America?
  • 4 weeks later...
On 9/4/2020 at 2:47 PM, Omnomosaurus said:

I've recently had a little chat with Phil Currie around Tyrannosaurid teeth, and he mentioned the subject of enamel "crinkling".

 

Phil wasn't aware of any publication on the feature, but Jim Farlow apparently made the observation years ago that crinkling of the tooth enamel is a feature found solely on tyrannosaurine teeth, and is not present in those of the albertosaurinae.

 

Approx. 25% of tyrannosaurine teeth have enamel crinkles, but Phil is confident that the presence of them can be used as a diagnostic tool to confidently rule out the possibility of it belonging to an albertosaurine tyrannosaur.

 

A tooth lacking this enamel ornamentation can still belong to either the tyrannosaurine or albertosaurinae however.

 

Might be another useful diagnostic tool for a small portion of those Gorgosaurus/Daspletosaurus contenders.

Hi! I was reading this Id again to check for updates, and I saw this. Do you have an example of what enamel crinkling would look like? I have a tooth that I think may match this description but I couldn’t find any pictures online that described what enamel crinkling looks like. 

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  • 1 month later...

I was rereading "Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification" when I noticed this paragraph on the conclusion:

 

The mesial denticles for relatively mature specimens of Albertosaurus, Daspletosaurus, and Gorgosaurus, start closer to the base of the tooth in the maxilla, which is not true for the teeth of Tyrannosaurus rex.

 

Not sure if this point has been discussed yet but does it help to differentiate between T. rex and Nanotyrannus teeth? I have too few teeth to make an accurate comparison but on my large Nanotyrannus, the mesial denticles do end closer to the base than my T. rex does

 

 

962655599_Rex_(5).jpg

Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday!

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@-Andy-  interesting concept.   In that conclusion they were just looking to aid in the helping ID maxillary and dentary positions of Campanian Tyrannosaurids.   I'll look at my teeth and see if there is any difference in mesial travel between HC / Lance Tyrannosaurids and enough of a difference to talk with Pete.  In your example you are looking at an anterior dentary tooth to a non-typical large Nano and I'm not sure there is enough difference to differentiate the two but lets see what a greater sampling size says.   Would be nice to have more differentiators.

 

 

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@-Andy-  So I took a look at about 50 teeth and its just to difficult to conclusively differentiate the two by that method.   The mesial carina of Nano teeth are generally lower but some are a bit higher and equivalent to T rex teeth.    I have a 3" T-rex maxillary tooth similar to your Nano who's mesial carina extends to the base.   If the Nano's would extend to the base it would be black and white otherwise its too subjective.  I think you have to continue to look at the base shape and robustness of the tooth to make the call.   

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3 minutes ago, Troodon said:

@-Andy-  So I took a look at about 50 teeth and its just to difficult to conclusively differentiate the two by that method.   The mesial carina of Nano teeth are generally lower but some are a bit higher and equivalent to T rex teeth.    I have a 3" T-rex maxillary tooth similar to your Nano who's mesial carina extends to the base.   If the Nano's would extend to the base it would be black and white otherwise its too subjective.  I think you have to continue to look at the base shape and robustness of the tooth to make the call.   

 

Thanks Frank for taking the time out to check your teeth

Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday!

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  • Troodon changed the title to Identification Tyrannosaurid Teeth From North America
  • 3 months later...

Untitled document (1).pdf would this tooth be considered a tyrannosaurus rex tooth? it is 1.6 inches long and has serrations running on both sides of a tooth. Also what would be a good trade for a rex tooth? 

Edited by jacob86795
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17 minutes ago, jacob86795 said:

Untitled document (1).pdf would this tooth be considered a tyrannosaurus rex tooth? it is 1.6 inches long and has serrations running on both sides of a tooth. Also what would be a good trade for a rex tooth? 

Please post a photo. I dont download unknown files.  Also need a locality where found

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  • 2 months later...

Always a challenge to identify isolated teeth since the information is very fragmented and not easily available to the average collector.  Tried gathering some information from papers and included data from a study I did a while back to try to look at T rex and Nanotyrannus teeth.  The information presented on T rex includes Sue and Stan so the teeth are quite large.  I also separated Maxillary and Dentary teeth to see if there was any difference, there was to my surprise.  I also added a group from my personal collection to get a better cross-section of what the average collector would have.  

 

All this type of information is important to those of us who try to identify isolated teeth.

 

Tyrannosaurs rex: 

  Dentary Teeth (48 recorded)

  • CH (Crown Height) range: 18-97 mm
  • CBR (Crown Base Ratio) : Avg 0.73 (0.56-0.83) 
  • CHR (Crown Height Ratio) :  Avg 1.73 (1.2-2.3)
  • DSDI (Density Ratio Mesial/Distal) : Avg 0.97 (0.8 -1.14)
  • DSDI > 1.0 : 17%
  • Distal Density Avg: 1.73
  • Mesial Density Avg: 1.81

Maxillary Teeth (41 recorded)

  • CH range: 27-115 mm
  • CBR : Avg 0.68 (0.57-0.82)
  • CHR : Avg 1.95 (1.4-2.5)
  • DSDI : Avg 0.96 (0.80-1.16)
  • DSDI >1.0 : 41% 
  • Distal Density Avg : 1.67
  • Mesial Density Avg : 2.03

My Collection (Smaller teeth) Personal Observations (15 recorded)

  • CR range:  8-36 mm 
  • CBR : Avg 0.76 (0.55-1.8)
  • CHR : Avg 1.9 (1.2-2.6)
  • DSDI: Avg .99 (.86-1.15)
  • DSDI >1.0 : 20%
  • Distal Density Avg : 2.87

  • Mesial Density Avg : 2.90

     

Nanotyrannus lancensis:

(31 teeth recorded - personal observations)

  • CH range: 13-41 mm
  • CBR : Avg 0.52 (0.35-0.71)
  • CHR : Avg 2.13 (1.4-2.8)
  • DSDI : Avg 1.08 (.88-1.23)
  • DSDI >1.0 : 58% 
  • Distal Density Avg : 2.88
  • Mesial Density Avg : 3.09

 

T rex observations:

  • CBR & CHR Ratios between Maxillary and Dentary teeth of T rex are not that different.  CBR slightly different due to those wide anterior dentary teeth.
  • A much great number of Maxillary teeth have DSDI ratios of over 1:  41% (means the mesial carina has a higher density of serrations)
  • Although the average density between Mesial and Distal carinae of T rex teeth is similar the variation can be quite large and one cannot make the assumption they are identical.

Nanotyrannus observations:

  • 58% of the teeth observed had the mesial density greater than the distal carinae.  This is what makes diagnosing  Nanotyrannus & Dromaeosaurid teeth very difficult, especially in the 1 to 2 cm range.
  • CBR appears to be smaller than T rex teeth points to narrower crown
  • CHR a bit higher that points to a more elongated crown

 

References: 

-Heterodonty in Tyrannosaurs rex: implications for the taxonomic and systematic utility of theropod dentition:        J. B Smith 2010

-Dental Morphology and Variation in Theropod Dinosaurs: Implications for the Taxonomic Identification of Isolated teeth       J.B. Smith, David Vann, Peter Dodson 2005

 

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Thanks for collecting this information.   Nice to see it especially with Nanotyrannus teeth.   Those mesial carina numbers are a surprise and indeed it does not help one identify Dromaeosaurid teeth in the Hell Creek.  

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Just now, TyBoy said:

Thanks for collecting this information.   Nice to see it especially with Nanotyrannus teeth.   Those mesial carina numbers are a surprise and indeed it does not help one identify Dromaeosaurid teeth in the Hell Creek.  

 

Thanks, its indeed a challenge with those small compressed teeth and some may have to be indeterminate.  The other aspect is that we do not know what the dentition of the 2 or 3 Dromaeosaurids looks like.  Just a few teeth of two species have been described.   Hopefully someone finds a jaw full of teeth.

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  • 3 weeks later...
On 9/4/2015 at 3:26 AM, Troodon said:

Premaxillary Teeth

1) In my opinion all these teeth should be identified as "Tyrannosaurid indet"

2) The paper does make the following statement "In the young specimens of Daspletosaurus, the carinae of the premaxillary teeth are unserrated (TMP 1994.143.1; Currie, 2003) and show the beaded condition.  My concern is that it does not specify what size young teeth are and its looking at TMP 1994.143.1 which is a Daspletosaurus sp in Dinosaur Park Fm.  Do all Daspletosaurus premax teeth in other faunas have contain similar features?  Gorgosaurus premax teeth are not mentioned.

 

Hi there, I am afraid TMP 1994.143.1 might be reassigned to Gorgosaurus based off this recent paper:

 

https://prism.ucalgary.ca/bitstream/handle/1880/109240/ucalgary_2018_voris_jared.pdf?sequence=1&isAllowed=y

Edited by -Andy-
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Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday!

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42 minutes ago, -Andy- said:

 

Hi there, I am afraid TMP 1994.143.1 might be reassigned to Gorgosaurus based off this recent paper:

 

https://prism.ucalgary.ca/bitstream/handle/1880/109240/ucalgary_2018_voris_jared.pdf?sequence=1&isAllowed=y

 

Hey thanks for the paper.  Need to read it in full when I get home, pretty large paper.  Will be interesting to see if Currie et al. will agree with this potential reassignment.  Pretty significant change from a masters student paper.   Its the University of Calgary so I'm sure Phil Currie was involved.

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In the last week, I bought a tooth, the seller said it is from Lance Creek Fm., and it is a Tyrannosaurus rex tooth. its size 1-3/8 and base width 5/8.

While I think it's indeed the teeth of a T-Rex, I hope to ask more people to get more affirmative answers.

So, it is a real T rex tooth?

Thanks for your help

 

dt04-1e.jpg

dt04-2e.jpg

dt04-4e.jpg

dt04-5e.jpg

dt04-33.jpg

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1 hour ago, ChrisMouM said:

In the last week, I bought a tooth, the seller said it is from Lance Creek Fm., and it is a Tyrannosaurus rex tooth. its size 1-3/8 and base width 5/8.

While I think it's indeed the teeth of a T-Rex, I hope to ask more people to get more affirmative answers.

So, it is a real T rex tooth?

Thanks for your help

 

dt04-1e.jpg

dt04-2e.jpg

dt04-4e.jpg

dt04-5e.jpg

dt04-33.jpg

Definitely a Tyrannosaurid tooth.  Do you have a locality where it was found?  Its also Lance Formation not Lance Creek Fm.

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20 minutes ago, Troodon said:

Definitely a Tyrannosaurid tooth.  Do you have a locality where it was found?  Its also Lance Formation not Lance Creek Fm.

he just said that it collected on private land in the Lance Creek Fm., Niobrara Co., Wyoming. 

Do I need to ask for any other information

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In 2018, Dr Carr mentioned that D. torosus and A. libratus is found in the JRF

 

Link: https://vertpaleo.org/wp-content/uploads/2021/03/SVP-2018-program-book-V4-FINAL-with-covers-9-24-18.pdf

 

Interestingly, he used the name Albertosaurus libratus instead of Gorgosaurus libratus, but that aside - is this enough to prove that Daspletosaurus torosus and Gorgosaurus libratus are indeed described in the JRF?

 

 

Screenshot_20220923-114414_Acrobat for Samsung.jpg

Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday!

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