Kem Kem Theropod Teeth: what you need to know

[zekky]

I wonder if the people collecting the fossils are looking for ornithopod teeth. An Igunanodont should produce a lot of shed teeth.

[Troodon]

I like George, I consider him a friend and I definitely respect his opinion but in this case I have to disagree with him. In my opinion this tooth is a juvenile Carch.

Agreed and think Delta teeth to be more recurved being a smaller theropod.

[Troodon]

I wonder if the people collecting the fossils are looking for ornithopod teeth. An Igunanodont should produce a lot of shed teeth.

I'm sure they are collecting anything that looks like a fossil and cannot distinguish between species other than Spino or Carch., its money in their pocket. A number of ideas exist of why but they are just theories nothing concrete.

[Troodon]

I just received my quarterly SVP publication and one of the topic that attracted my attention was on "Dental terminology of non-avian theropods". They confirmed my beliefs that serrations (denticles) are the key in the identification of theropod teeth. A number of different example were shown and the diversity that exists between them. But what I found eye opening was that you need to look very closely at the denticles, 1 mm sections, to see differences that can be subtle and its all about denticle shape.

So I took a much closer look at those intermediate teeth that I called juvenile Carcharodontosaurus and it changed my conclusion on their identification.

These are the teeth in question.

This is an image of Carcharodontosaurus denticles from the SVP paper. The scale bar is 1 mm

This type of denticle is called "subquadrangular distocentral" definitely a technical term

This is an image of one of my Carch teeth and they look identical ( 2 denticles per mm )

Now here is a closeup of the denticles of one of the two teeth in question. Both teeth were the same so just showed one. With the super closeup you can see that they are different. They are narrower, more rounded and are called "proximodistally subrectangular distocentral" woweeeee thats a mouthful (3 denticles per mm )

Conclusions that I've made:

1) These two teeth should be identified as Theropod indet. and may be Deltadromeus but we cannot draw that conclusion without further evidence.

2) Closeup examination of the denticles of these type of teeth are necessary to determine if they are juvenile Carcharodontosaurus teeth or another Theropod. You cannot do it visually, a strong hand loop may help, but the best approach is a scope because of how similar the denticles can look. The size and shape of tooth are the first characteristic to get you to the next step a closer look at the serrations. Buying these type of teeth online can be risky and should be done with the ability to return them if necessary.

3) Serration count although helpful does not by itself identify species. Smaller teeth from younger animals tend to have a higher count than adults. Denticle shape is more critical in identification.

[-Andy-]

I just received my quarterly SVP publication and one of the topic that attracted my attention was on "Dental terminology of non-avian theropods". They confirmed my beliefs that serrations (denticles) are the key in the identification of theropod teeth. A number of different example were shown and the diversity that exists between them. But what I found eye opening was that you need to look very closely at the denticles, 1 mm sections, to see differences that can be subtle and its all about denticle shape.

So I took a much closer look at those intermediate teeth that I called juvenile Carcharodontosaurus and it changed my conclusion on their identification.

These are the teeth in question.

Carch3.jpg

This is an image of Carcharodontosaurus denticles from the SVP paper. The scale bar is 1 mm

This type of denticle is called "subquadrangular distocentral" definitely a technical term

Carch.jpg

This is an image of one of my Carch teeth and they look identical ( 2 denticles per mm )

CarchFF4RC.jpgCarchFF4RC1.jpg

Now here is a closeup of the denticles of one of the two teeth in question. Both teeth were the same so just showed one. With the super closeup you can see that they are different. They are narrower, more rounded and are called "proximodistally subrectangular distocentral" woweeeee thats a mouthful (3 denticles per mm )

CarchFF1RC.jpgCarchFF1RC1.jpg

Conclusions that I've made:

1) These two teeth should be identified as Theropod indet. and may be Deltadromeus but we cannot draw that conclusion without further evidence.

2) Closeup examination of the denticles of these type of teeth are necessary to determine if they are juvenile Carcharodontosaurus teeth or another Theropod. You cannot do it visually, a strong hand loop may help, but the best approach is a scope because of how similar the denticles can look. The size and shape of tooth are the first characteristic to get you to the next step a closer look at the serrations. Buying these type of teeth online can be risky and should be done with the ability to return them if necessary.

3) Serration count although helpful does not by itself identify species. Smaller teeth from younger animals tend to have a higher count than adults. Denticle shape is more critical in identification.

Assuming we are able to lock it down to a particular type of teeth based on their size and serrations, shouldn't we assign a temporary species name to it, to differentiate it from the other Theropod indet. teeth?

[Troodon]

IMO no, thats the cart before the horse. We cannot assign species based on just a isolated tooth. That was the practice back in the early days of Dinosaur hunting and its created many issues today. Part of describing a dinosaur is to assign it to the proper family and without skeletal remains how do you do that?

Edited October 16, 2015 by Troodon

[Auspex]

Assuming we are able to lock it down to a particular type of teeth based on their size and serrations, shouldn't we assign a temporary species name to it, to differentiate it from the other Theropod indet. teeth?

You could use "PSD Type", for "Proximodistally Subrectangular Distocentral".

This gives it a type-name, without implying a taxonomic relationship.

[-Andy-]

IMO no, thats the cart before the horse. We cannot assign species based on just a isolated tooth. That was the practice back in the early days of Dinosaur hunting and its created many issues today. Part of describing a dinosaur is to assign it to the proper family and without skeletal remains how do you do that?

If we can find dozens or even hundreds of teeth conforming closely to a particular size and serration type, that implies they are of the same family of theropod. Wouldn't it help then to class them together to await more identification than to let them get bundled up with all the other "Theropod indet."?

[Troodon]

We have that with Abelisaurid teeth but they have a unique shape to that family so we can pigeon hold them awaiting an ID. I'm not sure where you would place these teeth, the next step up in classification is theropod. Even the classification of Deltadromeus is uncertain.

[-Andy-]

We have that with Abelisaurid teeth but they have a unique shape to that family so we can pigeon hold them awaiting an ID. I'm not sure where you would place these teeth, the next step up in classification is theropod. Even the classification of Deltadromeus is uncertain.

I assume the Deltadromeus ID was a monkey-see-monkey-do thing which spiraled outta control with dealers. But George did mention the teeth he holds is one of the two types found associated with the Deltadromeus skeleton. Gastroliths and dinosaur eggs have been given ID(and gotten wrong at times too, look at Protoceratops) based on association with a skeleton; the question is, can we do the same for these teeth?

Troodon, could you post a pic of a confirmed Abelisaurid tooth next to the tooth you checked the serrations of? (At worst we will now label them Theropod Type A hahaha)

[Auspex]

The monkey-see-monkry-do phenomenon is why I am loath to assign more that form-names to parts without iron-clad affinities.

Give something a species name, and in no time flat it becomes true.

[Troodon]

Andy

The easiest way to ID a Kem Kem Abelisaurid tooth is what I show at the end of page 1. The shape is unique to this type of tooth.

Edited October 17, 2015 by Troodon

[-Andy-]

The monkey-see-monkry-do phenomenon is why I am loath to assign more that form-names to parts without iron-clad affinities.

Give something a species name, and in no time flat it becomes true.

My dilemma regarding this is that it makes it much easier for ppl to get into the hobby.

For example, most dinosaur eggs cannot be identified down to the species. Yet when I held one in front of a crowd and told them how it was a theropod egg called Elongatoolithus, the response was lackluster. When I called it an Oviraptor egg however, someone piped up, "Raptor, like Velociraptors?"

Next thing I knew, the crowd surged forward, and everyone wanted to hold the "raptor egg".

Andy

The eadiest way to ID a Kem Kem Abelisaurid tooth is what I show at the end of page 1. The shape is unique to this type of tooth.

Oops, forgot about that. Yeah you're right, the shape is quite different from Abelisaurid.

[Troodon]

The monkey-see-monkry-do phenomenon is why I am loath to assign more that form-names to parts without iron-clad affinities.

Give something a species name, and in no time flat it becomes true.

Agreed but lots of collectors and dealers love to see species names. Theropod indet appears to carry a negative stigma from both the selling or buying side.

[Dracorex_hogwartsia]

Agreed but lots of collectors and dealers love to see species names. Theropod indet appears to carry a negative stigma from both the selling or buying side.

You know, I can care less. I don't care what species name a dealer puts on their fossil. I always take it with a grain of salt that they're wrong anyway! I don't claim to be an expert on dinosaurs by any stretch of the imagination but I do feel like I know as much or more than most dealers. What I don't know, I'll study and do research on. The internet is a great place if you'll take the time to use it. I've never understood why some collectors get so hung up on species names.

[-Andy-]

You know, I can care less. I don't care what species name a dealer puts on their fossil. I always take it with a grain of salt that they're wrong anyway! I don't claim to be an expert on dinosaurs by any stretch of the imagination but I do feel like I know as much or more than most dealers. What I don't know, I'll study and do research on. The internet is a great place if you'll take the time to use it. I've never understood why some collectors get so hung up on species names.

Let's just say to many collectors, there's a world of difference between owning a T. rex tooth, and a Nanotyrannus or worst, a misidentified crocodile.

[Dracorex_hogwartsia]

Let's just say to many collectors, there's a world of difference between owning a T. rex tooth, and a Nanotyrannus or worst, a misidentified crocodile.

That's why you need to know what you're doing. Be smart, become as knowledgeable about what you're collecting as possible and don't just believe what dealers/sellers tell you.

[Troodon]

I think it's human nature, as a collector, to want to know exactly what you have, I do. Unfortunately collecting isolated theropod teeth is fraught with frustrations because the answers just may not be there no matter how much of an expert you are. We all have to accept that discovery is not something you can plan for or schedule but with luck may happen sooner than later.

[-Andy-]

What do you folks think of this Kem Kem tooth?

It was sold to me as Deltadromeus, It has a somewhat similar profile to small Carch, but is far skinnier with a thickness of 0.35 inches. Straight line measurement is 2.03 inches.

Comparison with small Carch.

Any ideas what it actually is?

[Runner64]

What do you folks think of this Kem Kem tooth?

It was sold to me as Deltadromeus, It has a somewhat similar profile to small Carch, but is far skinnier with a thickness of 0.35 inches. Straight line measurement is 2.03 inches.

P1060857.jpg

Delta_5.jpg

Delta_6.jpg

Comparison with small Carch.

Any ideas what it actually is?

To me, it looks Carch. Maybe if you got a picture of the serrations, we could make a better guess as to what it is.

[Troodon]

Andy I think you've said everything you can on the tooth but without a closeup photo of the serrations I'm not willing to make that call. Learned my lesson with my teeth.

FYI: the scope I use for my serrations photos is a USB digital one that sells for well under $100 USD. I would recommend one for all serious theropod tooth collectors. Good investment to your precious tooth collection.

[-Andy-]

To me, it looks Carch. Maybe if you got a picture of the serrations, we could make a better guess as to what it is.

Andy I think you've said everything you can on the tooth but without a closeup photo of the serrations I'm not willing to make that call. Learned my lesson with my teeth.

FYI: the scope I use for my serrations photos is a USB digital one that sells for well under $100 USD. I would recommend one for all serious theropod tooth collectors. Good investment to your precious tooth collection.

Gotcha.

I was rather certain it wasn't Carch due to how skinny it was. My concern was whether this is a Carch or Theropod indet.

[Runner64]

Andy I think you've said everything you can on the tooth but without a closeup photo of the serrations I'm not willing to make that call. Learned my lesson with my teeth.

FYI: the scope I use for my serrations photos is a USB digital one that sells for well under $100 USD. I would recommend one for all serious theropod tooth collectors. Good investment to your precious tooth collection.

Is there a certain type of scope you would recommend?

[FossilHunter99]

Thanks for the guide! I have a small spinosaurus tooth

[Runner64]

What do you folks think of this Kem Kem tooth?

It was sold to me as Deltadromeus, It has a somewhat similar profile to small Carch, but is far skinnier with a thickness of 0.35 inches. Straight line measurement is 2.03 inches.

P1060857.jpg

Delta_5.jpg

Delta_6.jpg

Comparison with small Carch.

Any ideas what it actually is?

Hey Andy, just looked at my Carch teeth and one of mine looks just like the one you have except mine curves more. I have to agree, it doesn't look Carch but I would have to look at the serrations to be more accurate.