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Baby Tyrannosaur Teeth

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FossilsandScience

Hey everyone!

 

I have a quick question on baby tyrannosaur teeth and their rarity compared to adult or subadult tyrannosaur teeth. Which is rarer to find? I would assume baby tyrannosaur teeth would be rarer, but at the same time, most tyrannosaurs didn’t even make it to adulthood. So which would you say? Are baby tyrannosaur teeth or adult tyrannosaur teeth rarer? Any answer is appreciated! Thanks everyone!

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Praefectus

@Troodon How do you differentiate juvenile rex teeth from adult ones?

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Praefectus

Very interesting. I've seen a lot of isolated rex teeth that were labeled "juvie." Thanks for the information. 

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PaleoNoel

That's the one Dr. Steve Nicklas found w/PaleoProspectors. I'm surprised it doesn't get talked about more in the Nano debate.

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hadrosauridae
12 hours ago, Praefectus said:

Very interesting. I've seen a lot of isolated rex teeth that were labeled "juvie." Thanks for the information. 

Thats because sellers who dont believe that "nano" is its own species label all small tyranosaurid teeth as juvenile.

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Troodon
10 hours ago, PaleoNoel said:

That's the one Dr. Steve Nicklas found w/PaleoProspectors. I'm surprised it doesn't get talked about more in the Nano debate.

Well Pete Larsen has consistently used that jaw to compare against Nanotyrannus ones.   The problem being its privately owned and the primary advocate against two species refuses to consider anything that is not in the holy sanctum of a museum 

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Praefectus
39 minutes ago, hadrosauridae said:

Thats because sellers who dont believe that "nano" is its own species label all small tyranosaurid teeth as juvenile.

I was talking more about when sellers haphazardly label anything small as juvenile. I agree, there are a lot of mis-labeled nano teeth out there too. 

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Troodon

What I've seen is lots of very small tyrannosaurid teeth labeled as Dromaeosaurid or Dromaeosaur just out of ignorance.  Lots of sellers are just clueless and just base identification based on size.

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FossilsandScience
3 hours ago, Troodon said:

What I've seen is lots of very small tyrannosaurid teeth labeled ad Dromaeosaurid or Dromaeosaur just out of ignorance.  Lots of sellers are just clueless and just base identification based on size.

I’ve seen this very often as well. One seller listed a tooth as a Dromeosaurid and I bought it because it looked tyrannosaur to me. Ended up being a hatchling T. Rex tooth (the tooth was about 9-10mm)! Looking very closely at teeth labeled Dromeosaurid can pay off! 

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Troodon
45 minutes ago, FossilsandScience said:

I’ve seen this very often as well. One seller listed a tooth as a Dromeosaurid and I bought it because it looked tyrannosaur to me. Ended up being a hatchling T. Rex tooth (the tooth was about 9-10mm)! Looking very closely at teeth labeled Dromeosaurid can pay off! 

Good point, Ive picked up some very nice material that was misidentified so it always pays try to identify it yourself and not rely on the sellers call.

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Jaimin013

Hi All,

 

I thought that I would make a contribution to this topic by posting a pic of my rooted juvenile tyrannosaurus rex tooth (first pic). I've only seen a few teeth like it. It was advertised as a dromaeosaurid tooth but having spoken to multiple people (including Pete Larson, Bucky Derflinger) they all lean towards it likely being a juvenile tyrannosaurus tooth because of how robust/banana shaped it is. The tooth looks different than most of the teeth that Troodon has posted in the jaw of baby Trex dentary (with the exception of perhaps the last tooth closest to the front of the jaw in the middle jaw pic) but as the root of the teeth are not exposed in the jaw it's difficult to make a comparison. Would be cool if a scan could be done on it someday which allows us to determine how the roots of the teeth look like. The shape of a tooth is likely to depend on tooth position so maybe that's why it doesnt match most of the teeth in that jaw.

 

@Dracarys I also have a tooth that is similar to yours (see third pic). Like Troodon says juvie sized teeth could simply be unerupted teeth from adults rather than a functional juvie so not sure how to tell. Although the tooth in the third pic is robust like trex teeth, it's hard to tell if the tooth in the third pic would be arguably different from the first tooth if it was rooted.

 

The life cycles/stages and terminology are all too confusing for me (baby, juvenile, adult... and how do you class something as a sub-adult... is it at the juvenile stage, is it past the juvenile stage and anywhere between juvenile and adult, when do you stop calling something a baby rather than juvenile (as juvenile just means young so I assume baby falls into that category) and are there slight differences in the way the teeth look depending on this on top of the differences in tooth shape depending on the location in the jaw. Perhaps the third tooth may look similar to the first tooth if it was rooted rather than shed i dont know. As you can see in the fourth pic comparing all of my nano/rex teeth side by side it's not impossible.

 

I've seen a few other pics of juvenile rex teeth including from individuals such as baby bob (see last pics of Baby Bob's teeth) which look different than the tooth in my first pic which may be due to tooth position or perhaps maybe teeth like the ones myself and @Dracarys have posted are more closer to baby than juvenile or sub-adult. This goes back to how difficult it is to make a call with isolated teeth and not being able to see the bigger picture with rest of the teeth in a jaw.

 

Regarding rex vs nano, the second pic is a rooted Nanotyrannus tooth found by PaleoAdventures (if anyone is interested). Obviously, you can see that rex teeth are different than nano. Just look at how robust rex teeth are compared with Nano. It also helps when you can compare fully rooted teeth.

 

Anyway I am probably going off topic/ranting but going back to the original question by @FossilsandScience I would say yes baby teeth are rarer. I just don't see them as often. It's also very difficult to call with small teeth whether it's nano rather than rex especially when you sometimes find "in-between teeth" which are hard to differentiate like the one in the fourth pic, fourth tooth.

inCollage_20200609_202051773.jpg

D_j1xudXYAEy4LB.jpg20200415_094627395.jpg

20190804_141959.jpg.2d97765d3c1e0b684085cda570abf534.jpg

 

 

Baby Bob teeth

post-20707-0-99238900-1455790044.jpgpost-20707-0-77535700-1455790030.jpg

post-10935-0-33044800-1455316558.jpg

post-10935-0-55176100-1455316541.jpg

post-10935-0-10555800-1455316531.jpg

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Dracarys
3 hours ago, Jaimin013 said:

Hi All,

 

I thought that I would make a contribution to this topic by posting a pic of my rooted juvenile tyrannosaurus rex tooth (first pic). I've only seen a few teeth like it. It was advertised as a dromaeosaurid tooth but having spoken to multiple people (including Pete Larson, Bucky Derflinger) they all lean towards it likely being a juvenile tyrannosaurus tooth because of how robust/banana shaped it is. The tooth looks different than most of the teeth that Troodon has posted in the jaw of baby Trex dentary (with the exception of perhaps the last tooth closest to the front of the jaw in the middle jaw pic) but as the root of the teeth are not exposed in the jaw it's difficult to make a comparison. Would be cool if a scan could be done someday on it which allowed us to determine how the roots of the teeth look like. The shape of a tooth is likely to depend on tooth position so maybe that's why it doesnt match most of the teeth in that jaw.

 

@Dracarys I also have a tooth that is similar to yours (see third pic). Like Troodon says juvie sized teeth could simply be unerupted teeth from adults rather than a functional juvie so not sure how to tell. Although the tooth in the third pic is robust like trex teeth, it's hard to tell if the tooth in the third pic would be arguably different from the first tooth if it was rooted.

 

The life cycles/stages and terminology are all too confusing for me (baby, juvenile, adult... and how do you class something as a sub-adult... is it at the juvenile stage, is it past the juvenile stage and anywhere between juvenile and adult, when do you stop calling something a baby rather than juvenile (as juvenile just means young so I assume baby falls into that category) and are there slight differences in the way the teeth look depending on this on top of the differences in tooth shape depending on the location in the jaw. Perhaps the third tooth may look similar to the first tooth if it was rooted rather than shed i dont know. As you can see in the fourth pic comparing all of my nano/rex teeth side by side it's not impossible.

 

I've seen a few other pics of juvenile rex teeth including from individuals such as baby bob (see last pics of Baby Bob's teeth) which look different than the tooth in my first pic which may be due to tooth position or perhaps maybe teeth like the ones myself and @Dracarys have posted are more closer to baby than juvenile or sub-adult. This goes back to how difficult it is to make a call with isolated teeth and not being able to see the bigger picture with rest of the teeth in a jaw.

 

Regarding rex vs nano, the second pic is a rooted Nanotyrannus tooth found by PaleoAdventures (if anyone is interested). Obviously, you can see that rex teeth are different than nano. Just look at how robust rex teeth are compared with Nano. It also helps when you can compare fully rooted teeth.

 

Anyway I am probably going off topic/ranting but going back to the original question by @FossilsandScience I would say yes baby teeth are rarer. I just don't see them as often. It's also very difficult to call with small teeth whether it's nano rather than rex especially when you sometimes find "in-between teeth" which are hard to differentiate like the one in the fourth pic, fourth tooth.

inCollage_20200609_202051773.jpg

D_j1xudXYAEy4LB.jpg20200415_094627395.jpg

20190804_141959.jpg.2d97765d3c1e0b684085cda570abf534.jpg

 

 

Baby Bob teeth

post-20707-0-99238900-1455790044.jpgpost-20707-0-77535700-1455790030.jpg

post-10935-0-33044800-1455316558.jpg

post-10935-0-55176100-1455316541.jpg

post-10935-0-10555800-1455316531.jpg

Nice pictures and comparisons. My tooth has fair amount of tip wear --> he was definitely using it. :)

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hadrosauridae

Great photos.  This is the only baby-Rex tooth I've found.

 

20190801_194625.thumb.jpg.b5293949a5cbc0e932ca6c2a45f5f0bd.jpg

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jdp
On 8/3/2020 at 5:58 PM, Troodon said:

No idea on isolated teeth :)  juvie sized teeth could simply be unerupted teeth from adults.  Presence of wear facets can identify functional teeth.

 

Here is a baby Trex dentary with some nice size teeth

5f28a8d197283_ReplicaJaw2.thumb.jpg.931d425a454dd123ba0c2d5b5fcadd22.jpg

A 35 cm dentary is still quite a bit larger than a neonate.

 

I'm aware of one possible neonatal or embryonic jaw, which may be published at some point soon. We'll see.

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FossilsandScience

This is my baby Rex tooth here! You can tell it isn’t an unerupted tooth because it has some feeding wear. 

EFAFDB9E-9B11-4495-BBA3-708A6E3A6B7D.jpeg

6BC8142E-F92D-4EFE-97AF-1B80055481B5.jpeg

75CADF47-E3EE-44CC-9631-55B2C88CAF92.jpeg

2619A076-0115-463C-8B53-6BF96552D520.jpeg

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