Nanotyrannus-Tyrannosaurus transitional teeth.

[WhodamanHD 3,072]

We were having a discussion on the validity of Nanotyrannus Here, and I have a question for all you theropod tooth collectors. 

 

Many say that Nanotyrannus lancensis is a adolescent Tyrannosaurus rex. Now some here have many teeth from both. Nanotyrannus has gracile, thinner teeth, whereas tyrannosaurus has robust, thick teeth. If N. Lancensis is a juvenile form, than we should expect to see a transition in teeth from slender to thick. In other words, a spectrum of teeth. Do any of you collectors have this represented in your collection? Or a transitional tooth? Please do post pictures.

 

Now it is possible that there is one day a sudden change from one form to the other, but I’ve not seen anything to indicate that to be the case (if you do please share it). 

 

I will I’ll add I don’t have any of either teeth, and this is purely to satisfy my curiosity.

[-Andy- 2,162]

I am skeptical about the claim "majority of the scientific community".

 

How do we weight this figure? Have a survey ever been done for the top minds in the paleontology community?

 

Wouldn't it be more accurate to state: Consensus is divided on the validity of Nanotyrannus lancensis

[WhodamanHD 3,072]

7 minutes ago, -Andy- said:

I am skeptical about the claim "majority of the scientific community".

 

How do we weight this figure? Have a survey ever been done for the top minds in the paleontology community?

 

Wouldn't it be more accurate to state: Consensus is divided on the validity of Nanotyrannus lancensis

Going off the word of @Boesse and @CBchiefski, both part of the scientific community. I’ll edit it to make it more neutral.

[-Andy- 2,162]

I've noticed that collectors with multiple Hell Creek Tyrannosaurid teeth tend to believe in a T-Rex and Nanotyrannus divide.

 

Do we have any collector here with a collection of these teeth who believe Nanotyrannus is a juvenile Rex? I'm excluding dealers, because I've noticed dealers inflating their Nanotyrannus prices and calling it Rex.

[bcfossilcollector 131]

Interesting question. All of the T. rex teeth I have in my collection are juvenile(4) barring one rex tooth that is significantly larger than the other four. Oddly enough my one Nanotyrannus tooth is at least the length of the largest rex approaching or about two inches. Even the smallest tooth at about 9/16s of an inch is thick with large serrations. All of my rex teeth are robust in proportion to the much longer Nanotyrannus tooth. Having said this I realize my collection is not nearly big enough to be considered representative and I look forward to the expert observations of the major theropod collectors. I don’t have pictures of the Nano tooth handy , have to take some, but if you think it’s relevant I can post the pictures of that tooth along with some of the rex teeth when I get a chance. 

 

[WhodamanHD 3,072]

2 minutes ago, -Andy- said:

I've noticed that collectors with multiple Hell Creek Tyrannosaurid teeth tend to believe in a T-Rex and Nanotyrannus divide.

 

Do we have any collector here with a collection of these teeth who believe Nanotyrannus is a juvenile Rex? I'm excluding dealers, because I've noticed dealers inflating their Nanotyrannus prices and calling it Rex.

I’ve noticed the same. I also think the juvenile T. rex teeth you have are interesting.

 

anyway, gonna tag some collectors. I know Going to miss some but:

@Troodon @hxmendoza @lone5wolf117 @Masp 

Too late to remember more.

[bcfossilcollector 131]

3 minutes ago, -Andy- said:

I've noticed that collectors with multiple Hell Creek Tyrannosaurid teeth tend to believe in a T-Rex and Nanotyrannus divide.

 

Do we have any collector here with a collection of these teeth who believe Nanotyrannus is a juvenile Rex? I'm excluding dealers, because I've noticed dealers inflating their Nanotyrannus prices and calling it Rex.

If someone asked me without any of my prior knowledge regarding the teeth I have whether I thought they were from the same creature I would have excluded the Nano tooth from the rest. 

[WhodamanHD 3,072]

5 minutes ago, bcfossilcollector said:

don’t have pictures of the Nano tooth handy , have to take some, but if you think it’s relevant I can post the pictures of that tooth along with some of rex teeth when I get a chance. 

Sure, all nano and rex pictures are welcome! 

[Jaimin013 1,262]

Thought i would share. Originally thought to be nano but is likely rex.

[-Andy- 2,162]

@Jaimin013 Do you know the exact locality of this tooth?

 

I had a tyrannosaurid tooth I showed to Troodon once that looked somewhat similar. It didn't seem robust enough to be Rex yet it was too robust for Nano. Even he was puzzled. I went back to recheck my locality info and realized it was from Judith River Formation and not Hell Creek.

[Troodon 19,384]

The Tyrannosaurid teeth in my collection range from baby to adult and you can see the difference in morphology between the fat Trex teeth and gracile Nano teeth regardless of age.   Maxillary teeth become more problematic and can be difficult, on some teeth, to assign them to either.   Small Pre-max teeth are indistinguishable between the two species.  Identifying a mid/small range size tooth as adult or juvenile can also be very problematic because replacement teeth of adults can be small.

 

Dealers selling Tyrannosaurids teeth from the Lance/Hell Creek do discriminate between species as far as I can tell.   Proper identification issues is a bigger problem

Edited August 29, 2018 by Troodon

[Jaimin013 1,262]

7 hours ago, -Andy- said:

@Jaimin013 Do you know the exact locality of this tooth?

 

I had a tyrannosaurid tooth I showed to Troodon once that looked somewhat similar. It didn't seem robust enough to be Rex yet it was too robust for Nano. Even he was puzzled. I went back to recheck my locality info and realized it was from Judith River Formation and not Hell Creek.

@-Andy- From the Hell Creek formation, Powder River County, Montana USA. Tooth collected in 2011 also featured in my collection post. Henry also thinks it leans more to rex

[Masp 801]

https://youtu.be/kQa11RMCeSI

 

It’s a tough call. Did we all see this Ted talk with Jack Horner? 16:08 is where he talks about Tyrannosaurus vs Nanotyrannus. It’s convinving, but honestly I’m not sure what to believe. It’s something I have to research much more.   

[Troodon 19,384]

55 minutes ago, Jaimin013 said:

@-Andy- From the Hell Creek formation, Powder River County, Montana USA. Tooth collected in 2011 also featured in my collection post. Henry also thinks it means more to rex

You mean leans more to rex or locality is important?

[Jaimin013 1,262]

4 hours ago, Troodon said:

You mean leans more to rex or locality is important?

yes silly autocorrect changing my words... leans lol

[Boesse 1,741]

Until any of this is analyzed quantitatively using a large sample size and statistics showing two clusters of tooth morphologies within morphospace on a graph - none of this "I've got two nano teeth and four rex teeth" discussion really means much, I'm afraid.

[WhodamanHD 3,072]

14 minutes ago, Boesse said:

Until any of this is analyzed quantitatively using a large sample size and statistics showing two clusters of tooth morphologies within morphospace on a graph - none of this "I've got two nano teeth and four rex teeth" discussion really means much, I'm afraid.

It is speculative.

whether Nanotyrannus or juvenile rex, there is very clearly two different morphs as theropod collectors have known for a long time. 

This thread wasn’t really meant to turn into a debate as to whether one was a different species, just looking for relevant evidence evidence of a tooth transition. Given the large collections I would be surprised if it did exist and no one here had it.

I must say, for the record, I think the two will end up being different species. I can remember many examples when prolific collectors noticed differences far before the scientific community got ‘round to excepting them. The Giant thresher was thought to be a C. hastalis posterior and neglected by researchers for a long time, Collectors noticed (on TFF no less) megalolamna before it was described. That is not to say more work doesn’t need to be done, it very much does. And what do I know, I don’t even own one.

[WhodamanHD 3,072]

Now @Jaimin013s tooth is a good candidate for a transitional tooth. Here’s Andy’s teeth next to it (sorry to keep stealing you pics Andy!)

[Troodon 19,384]

The way I look at these teeth is that it has nothing to do with transition but position.  The middle tooth is a Trex Maxillary tooth while the one on the right is a dentary tooth.  Andys tooth is a Nanotyrannus  

[-Andy- 2,162]

29 minutes ago, WhodamanHD said:

Now @Jaimin013s tooth is a good candidate for a transitional tooth. Here’s Andy’s teeth next to it (sorry to keep stealing you pics Andy!)

 

 

It's okay to use my teeth pictures.

 

For added info, the crown-only measurement of my tooth in a straight line is 55 mm.

[bcfossilcollector 131]

11 hours ago, Boesse said:

Until any of this is analyzed quantitatively using a large sample size and statistics showing two clusters of tooth morphologies within morphospace on a graph - none of this "I've got two nano teeth and four rex teeth" discussion really means much, I'm afraid.

I stated as much in my previous post. A small sample is not broadly  representative of a population unless of course that population is itself very small. However, the point being made is that there are a lot of T. rex teeth that have been found and studied ,adult and juvenile ,including  teeth associated with rex jaws. Do any of these teeth bear any resemblance to the teeth attributed to the dubious Nanotyrannus? In any event I won’t bother posting any images in this thread as not  to burden the forums resources. Always appreciate your informative and knowledgeable posts. Much food for thought.