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T. rex or Nanotyrannus?


The_bro87

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Hello! I got this tooth as a Christmas present, and to me it looks like a T.rex tooth, but the shape of the base made me less sure. I was hoping someone could help get a accurate id. The tooth is 10/16 of an inch long, and was found in Garfield county Montana.It has similar serrations on both sides, so I thought it was a tyrannosaur tooth. The shape, lack of pinching at the base, and thickness made me think it was T.rex, and the base looked to me like it could be a maxillary tooth since it was more rectangular than oval, but I wanted to see if anyone thought it looked more like a Nanotyrannus tooth. I can take any more pictures that would be helpful. Merry Christmas! 

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A very nice Tyrannosaur tooth you've got there. (I had my eye on it at one point - glad someone got it :).) It's from a (juvenile?) Nanotyrannus. The base is rectangular as you pointed out, and is compressed. For future reference, the formation is also useful for ID, though in this case I think Hell Creek is the only possibility.

 

Another juvenile Nano for comparison: 

 

IMG_0500.thumb.jpeg.dfb83d2b2d3b4be2588099ef6c1fd8ff.jpeg

 

I do see some "pinching:"

 

85BDBB60-AE6D-4428-B3B2-031DA4C46C23.thumb.jpeg.668fb29fb6577b1090b16e9e6f067a7c.jpeg.168b8ef18c71a290454e4060d1ebb760.jpeg

 

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"Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan

"I was born not knowing and have had only a little time to change that here and there." - Richard Feynman

 

Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | SquamatesPost Oak Creek | North Sulphur RiverLee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone

Instagram: @thephysicist_tff

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Thank you very much! Looking at it now, I do see the pinching it’s just a little tough to see since the tooth is small. I’m very happy to know what this tooth is, and it’ll also be a great reference for other teeth I collect. I really like this tooth, and it’s probably my nicest Nanotyrannus tooth. 

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Hi, while I agree that there is a pinch at the base, some maxillary T-Rex teeth can have a similar profile.
That being said, the tooth does not look that compressed to me and the tip is very robust, not typical traits of Nanotyrannus. Also, most Nanotyrannus teeth show a twist of the mesial carina, not seen here. Do you have a close-up of the carinae so we can see how robust they are?
Any Tyrannosaurid-experts around to weigh in? ;)
 

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Here’s the photo, the Mesial side serrations are straight as they get closer to the base, and have a slight twist towards the very end. I’ll post a close up of the serrations in a moment. 

CC7C60BA-F2B2-49C6-A148-6C017F9FBED8.jpeg

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Here’s a picture of the distal side, and a picture showing both sides. It was a little hard to get a good picture of the Mesial serrations, so if another picture is needed I can take a new one. Thank you all so much for the help! 

C4A9578A-6795-43C0-BE6E-EFDDA397F560.jpeg

25F0A9C2-4791-43FE-BAA5-B2AAD420A9BA.jpeg

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you're fast =)  
with those thick denticles and the robust tip I am very much in the T-Rex camp. Let's wait what the professionals have to say, a nice tooth either way!

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I don't mean to speak for @Troodon (hope you're feeling much better, and that you have a speedy recovery), but when I had shown it to him a couple of months ago, he thought it was Nano.

"Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan

"I was born not knowing and have had only a little time to change that here and there." - Richard Feynman

 

Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | SquamatesPost Oak Creek | North Sulphur RiverLee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone

Instagram: @thephysicist_tff

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I agree that it looks more like a nano, but the shape definitely made me wonder if it could be rex. Either way I still think it’s a great tooth

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On 12/27/2020 at 6:48 AM, JoeS said:

Hi, while I agree that there is a pinch at the base, some maxillary T-Rex teeth can have a similar profile.
That being said, the tooth does not look that compressed to me and the tip is very robust, not typical traits of Nanotyrannus. Also, most Nanotyrannus teeth show a twist of the mesial carina, not seen here. Do you have a close-up of the carinae so we can see how robust they are?
Any Tyrannosaurid-experts around to weigh in? ;)
 

I disagree with “most Nanotyrannus teeth show a twist of the mesial carina”. Tyrannosaurus rex also shows this on positional teeth. As do other tyrannosauridae.

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Personally, I think more measurements and clearer photos need to be made. The shape of the base does not rule out a juvy rex posterior maxillary tooth. Rex maxillary teeth are more rectangular in cross section at the base they can show subtle indenting as seen on this tooth. It’s not really showing pinching. 
 

And proportionately, for the size of the tooth, it could go either way. It’s one of those problematic in between teeth. So I won’t commit to an ID in either direction.

 

Get denticle counts and plug them into @Troodon’s posted numbers. That would be a good start.

 

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Thank you! I’ll be sure to do that. Hopefully that makes it more clear. I can post whatever photos are helpful, so if a better close up of serrations would help I can post those after I take measurements. Also, I was looking through my collection and on a tooth that I’m fairly sure is a rex tooth, I noticed a twist on the Mesial side which I thought was interesting. 

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I tooth the serration/mm count, but I’m not sure if I did it correctly, so I can try again if so. I ask wasn’t sure which numbers from Troodon you meant, but I have the counts here with the picture I used to find them. On the Mesial side, I counted 5 serrations per millimeter, over a 4 mm scale. On the distal edge I counted about 4.5 serrations per millimeter, over a 7 mm scale. I tried to take the count from the mid section of each tooth, but the Mesial side was more difficult since the serrations stopped short of the base, and the distal went almost to the base. If either picture looks like it didn’t accurate or like a new count would help, I’d be happy to do it again. Thank you again for the help! 

F41DFF34-E21A-45FD-A245-FE92D48E2F67.jpeg

0E5E7BC3-A772-41CD-8872-C5A2F48AF434.jpeg

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2 hours ago, hxmendoza said:

Get denticle counts and plug them into @Troodon’s posted numbers. That would be a good start.

 

I don't think that's very useful in this case, according to:

 

 

"With small teeth since serrations density is not a differentiator the other characteristics of the tooth plays a key roll.  I've found that maxillary teeth can be the most difficult to differentiate and a few teeth are just indeterminate, at least with me. 

 

The best way to distinguish between the two morphology the shape at the base, compression of the crown and tip and if there is a pinch at the base."

 

2 hours ago, hxmendoza said:

It’s one of those problematic in between teeth.

Yes, I agree. Regardless, those serrations are perfect! :drool:

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"Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan

"I was born not knowing and have had only a little time to change that here and there." - Richard Feynman

 

Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | SquamatesPost Oak Creek | North Sulphur RiverLee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone

Instagram: @thephysicist_tff

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I also thought this tooth had really nice serrations compared to a lot of my other teeth! Right now I agree that it’s a pretty in between tooth, and Certainly hard to tell. I’m not sure if there’s any concrete way to tell, but if there is I am happy to provide pictures! I hope it can be made clear what type of tooth it is. I was also wondering, if thickness of the tooth is necessarily an indicator, and if there’s any large T. rex teeth that have a thinner profile. I thought I’d seen one for sale before, and I was just curious because it seems a lot of the time the teeth that are the hardest to tell are thinner. Thank again!  

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9 minutes ago, The_bro87 said:

I tooth the serration/mm count, but I’m not sure if I did it correctly, so I can try again if so.

Just being pedantic, but it's important (especially for smaller serrations) to measure using the same point on each hash mark like so:

 

F41DFF34-E21A-45FD-A245-FE92D48E2F67.thumb.jpeg.71ac08b78a0a8868ded46c80d10250f4.jpeg.cb7efa0dd05d89df9354626fee91d8dd.jpeg

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"Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan

"I was born not knowing and have had only a little time to change that here and there." - Richard Feynman

 

Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | SquamatesPost Oak Creek | North Sulphur RiverLee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone

Instagram: @thephysicist_tff

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