A collection of Dromaeosauridae teeth

[JoeS]

A small update:

 

#12

I obtained a nice premaxillary tooth of Saurornitholestes langstoni from the Judith River Fm. The mesial carina shows a prominent twist, note the placement of both carinae in the cross section, textbook ‘J‘ shape. The moderate twisting of the mesial carina onto the lingual side, and the still relatively compressed cross section suggest to me it’s either a 3^rd or 4^th premax. tooth. There are two short ridges on the lingual surface.

 

 

 

#13

An interesting positional tooth of Acheroraptor temertyorum from the Hell Creek Fm., as identified by the prominent ridge on the lingual side and shape of the distal denticles. The distinct elongated shape of the tooth and the oval cross section led me to speculate that this is an anterior dentary tooth. Of note is the unserrated mesial carina which almost immediately twists onto the lingual side.
I am very open to suggestions on this particular specimen.

 

 

[Troodon]

Nice adds.  I've seen teeth like you second one but since we have nothing to compare against hard to confirm your assignment.   Are there serrations on the mesial edge?  Could be a Nanotyrannus with the twist in that carina. I would email D. Evans or P Currie and see what they say.  

[JoeS]

3 minutes ago, Troodon said:

I would email D. Evans or P Currie and see what they say

Thanks @Troodon, I'll send them some pictures and update my post here accordingly.
And no, there is no trace of serrations on the mesial carina.

[Troodon]

My vote given the shape of the base is Nano

[JoeS]

On 1/22/2021 at 2:59 PM, JoeS said:

#13

An interesting positional tooth of Acheroraptor temertyorum from the Hell Creek Fm.

I heard back from Philip Currie:
"... it falls within the range of variability that I would expect to see for a dromaeosaurid, and therefore it probably is an Acheroraptor tooth. The elongate shape of the crown, the shape of each serration, the cross-section of the tooth and the non-denticulate mesial carina all are things I would expect to see in some of the teeth in the jaw, even if they do not match the ones that we described. From the shape I would guess that it is an anterior tooth, ... "
It's just great that scientists like him take the time to help us collectors out, in addition to fellow TFF members of course! Looking forward to new material being published.

[Troodon]

9 minutes ago, JoeS said:

I heard back from Philip Currie:
"... it falls within the range of variability that I would expect to see for a dromaeosaurid, and therefore it probably is an Acheroraptor tooth. The elongate shape of the crown, the shape of each serration, the cross-section of the tooth and the non-denticulate mesial carina all are things I would expect to see in some of the teeth in the jaw, even if they do not match the ones that we described. From the shape I would guess that it is an anterior tooth, ... "
It's just great that scientists like him take the time to help us collectors out, in addition to fellow TFF members of course! Looking forward to new material being published.

He's the go to guy great to know

[JoeS]

#14

I added another interesting positional tooth of Acheroraptor temertyorum from the Hell Creek Fm.
It's very compressed, have not seen this before. It also features a rather flat and a more convex side, so maybe a premaxillary tooth, though the mesial carina is straight (compare to #6). While the upper part of the mesial carina is worn, there is no evidence of denticles.

[JoeS]

#15

Next up something more mysterious, a Theropod indet. tooth from the Judith River Fm.
I initially thought it could be a Dromaeosaurus albertensis tooth given the early twist of the mesial carina.

I contacted Prof. Philip Currie for a possible ID. His analysis was very interesting:
He said they have many teeth like this one in their collections and they can neither assign them to a Dromaeosaurid nor to a Tyrannosaurid with certainty. He rules out Dromaeosaurus since the mesial carina twist is not strong and obvious enough (!), and while the overall shape looks more like a Tyrannosaurid it does lack clearly defining characters.
So he/we need to find such a tooth in a jaw, sounds pretty exciting!

[JoeS]

I have been on the lookout for a Dromaeosaurid tooth from the Kem Kem Beds for a long time now, as have many others

So far, I did not come across anything that would fully convince me, well that’ll anyway only happen if something gets published, but I know they are out there.

While there are many great threads here on TFF about Kem Kem tooth morphologies, I wanted to showcase the most striking teeth I have in my collection when it comes to something Dromaeosaurid-like.

 

#16

First off, a typical small Abelisaurid tooth to compare against. These teeth are not recurved, both carinae are straight, serrated and go all the way down to the base.

The serrations in this example are a bit hooked towards the tip of the tooth with a similar denticle count on the mesial and distal carina.

The tooth is compressed, a feature that might be more pronounced in the elusive Dromaeosaurid-like tooth.

Just a side note: the colors of the teeth coming out of the Kem Kem are just stunning!

 

 

#17

Here my first candidate. A recurved and compressed tooth. Serration density mesial and distal is different as is the height of the denticles. Note the prominent transverse undulations on the crown.

I contacted Dr. Christophe Hendrickx about this tooth, and he was kind enough to take a look. He said that all the characteristics seen are similar to the dental morphology of Masiakasaurus from the late Cretaceous of Africa, so there is a high chance it belonged to a closely related Noasaurid.

 

 

 

#18

Next up another recurved tooth with a roundish-oval base in cross section.
Serration density and height are different comparing mesial to distal denticles. Note the prominent blood grooves on the distal carina.

There are no transverse undulations present on the crown, so it seems to be a different morphology than #17.

 

 

 

#19

This tooth features some intriguing characteristics I had not seen before.

It has a small and smooth crown with oval cross section. Serration density distal and mesial is different, and it features some crisp unworn distal serrations, note their small height.

The mesial serrations are completely worn; however, the carina is clearly visible, extends 1/3rd down from the tip, and shows a slight lingual twist.

What do you think?

 

 

 

#20

Finally, an example of a larger tooth morphology also described in detail by @Troodon. It features a very prominent lingual twist of the mesial carina. Note the blood grooves on the distal carina towards the base of the tooth.

With a crown height of 1,7 cm (0.67’’) this is a large tooth for a possible Dromaeosaurid.

 

 

That’s all I have or now, let’s see what else we can find out there

 

Edited December 19, 2021 by JoeS
too many images attached ;)

[Troodon]

Very nice presentation and very nice teeth.

Its interesting all the different morphologies we have.  Certainly not all from different species just your typical positional variation but which one go with the other?  I liked Hendrickx call on #17.  Lots of undulations on that tooth.  Not sure the lingual twist is indicative of a Dromaeosaurid, most smaller ones are straight but who knows in the KK. 

Its been disappointing that we've seen nothing published on teeth for quite some time and no definitive call yet on the existence of Dromaeosaurids, Megaraptors or anything besides Spino's.

[JoeS]

I recently visited the Museum of Natural History in Vienna, Austria.
If you are in the area, I highly recommend a visit, their collection and displays are superb!

Most relevant for the thread here: their amazing life-sized model of Deinonychus antirrhopus.
The level of detail is astonishing – enjoy

 

 

 

 

 

 

[JoeS]

I wanted to spend a little time discussing my yet unfinished quest to acquire a tooth of Dakotaraptor steini.

As you know, they are hard to find and difficult to ID, so I decided to showcase my best near-miss teeth

First off, I want to link @Troodon 's ID thread here, which has all the up-to-date ID information needed – thank you so much for this!

The major difficulties to ID these teeth really stem from the overlap in morphology with Nanotyrannus lancensis,
and the fact that only few Dakotaraptor teeth were described and analyzed.
The latter is the reason that teeth can only be assigned to Dakotaraptor if all the ID criteria are met.
Once more teeth are described these criteria might become less rigid, e.g. CH.

If a tooth fits the general description, before purchase, it’s important to take a step back (!) and make sure that:

•       there is a full documentation of its provenance
•       denticles are not worn
•       the mesial carina is visible
•       the base is intact 

If these points are not met, the tooth cannot be IDed as Dakotaraptor.

 

# 21
First, a ‘reference’ Nanotyrannus lancensis tooth I acquired.
I was particularly interested in denticle counts and denticle shape.
As expected, denticle count lies within what is published for Dakotaraptor. Unfortunately, dePalma et al., 2014 only gives a range for denticle counts but no ratios etc. for the individual teeth.
Denticles on this tooth are not chisel shaped but rather rounded, one of the described hallmarks of Dakotaraptor teeth.
This showcases very well that one must look at all the features of a tooth, as a single identifier might underlie variation.
The typical twist of the mesial carina, and the pinched rectangular base clearly identify this tooth as Nanotyrannus.
 

 

# 22
I purchased this tooth as Dakotaraptor steini, as it had been identified by a Paleontologist proficient in the Hell Creek Fm.
After a long exchange with @Troodon and information provided by @-Andy-, I concluded it is most likely a Tyrannosaurid for the following reasons:

• base profile can also fit Tyrannosaurid teeth
• denticle shape does fit someTyrannosaurid teeth
• slight deflection of the mesial carina from the midline
• and finally, I could not get a solid provenance on the tooth ...

 

# 23
cf. Nanotyrannus lancensis.
One of my first teeth, and still my favorite.
I posted it here on TFF for identification. The tooth seems to be from an anterior position in the jaw as indicated by the slender morphology and placement of carinae – maybe from the dentary.
The rectangular cross section with a pinch on the lingual side strongly point towards Nanotyrannus. CHR lies outside of what is published for Dakotaraptor.
It is labeled as ‘cf.’ for now as the twisting of the mesial carina, cross section profile and CHR might be a function of its anterior position in the jaw, and the shape of denticles appears more rounded.
I want to see a Nanotyrannus jaw with teeth published, and one for Dakotaraptor

 

# 24
cf. Nanotyrannus lancensis.
Another tooth checking some of the Dakotaraptor ID boxes. However, both denticle shape and cross section do not fit that well.
The cross section shows pinching but not the typical rectangular shape, which might be positional.
Side note: it’s similar to cross sections of Acheroraptor teeth (see #8).

Denticles are slightly pointed apically and are asymmetric. Compare denticle shapes of #21, #23, and #24, there is quite some variation in Nanotyrannus.

In summary, looking for Dakotaraptor steini teeth is a real adventure, with ups and a bit more downs

I’ll make sure to post the real deal if I ever get a hold of one myself.

Edited July 28, 2022 by JoeS
too many images attached

[-Andy-]

Great photos and info. Your willpower is immense. Many folks would be content to label them cf. Dakotaraptor and call it a day

[Troodon]

Excellent post and info.  Hopefully others including sellers can gain insight into the proper identification of these elusive teeth.  Its unfortunate we do not have a better understanding of the dentition to help this along.  The Hell Creek however is very slow to give up its secrets.  Its through trial and error and $$$ that one will pop up for you.  

[Troodon]

8 hours ago, -Andy- said:

Many folks would be content to label them cf. Dakotaraptor and call it a day

Or accept the seller description

[JoeS]

10 hours ago, Troodon said:

Excellent post and info.  Hopefully others including sellers can gain insight into the proper identification of these elusive teeth.  Its unfortunate we do not have a better understanding of the dentition to help this along.  The Hell Creek however is very slow to give up its secrets.  Its through trial and error and $$$ that one will pop up for you.  

Thanks, I know only few sellers that try to look in depth at this kind of teeth. I can in part understand it, as it is tough and time consuming. The rest is sadly up to the buyer and trial and error as you said. Part of the reason why I put this thread up is to showcase all the differences and variation one encounters. Without TFF I would have been lost tbh, so I try to give something back.
 

10 hours ago, -Andy- said:

Great photos and info. Your willpower is immense. Many folks would be content to label them cf. Dakotaraptor and call it a day

Thanks! Ah well, that would be too easy
It would be great to have something that matches the publication, with that nice oval cross section. And there is a lot to learn along the way.
What keeps me motivated is that while it is a rare Dromaeosaurid tooth, at least there is a small chance to find one, there are others which are basically unobtainable.
 

[ThePhysicist]

Great information and the presentation of your collection is wonderful! It's surely among the highest-quality photography of theropod teeth on the forum. 

[Jared C]

Wow, happy I stumbled upon this thread! I cannot tell you enough how impressive your images are. 

[JoeS]

I finally came across a little Dromaeosaur bone I had to pick up, a humerus. It was found in two pieces and has been stabilized, both ends are a bit worn.
It was found in the Hell Creek Fm., so possibly from Acheroraptor temertyorum.

Was a bit surprised by how heavy it is. What a great color - a dream come true.