Telling Nanotyrannus Teeth From Dromaeosaur Teeth

[Carcharodontosaurus]

I have a Nanotyrannus/juvenile T. rex tooth that I acquired recently for my collection. However, I have noticed that many nano teeth are similar to large dromaeosaur teeth, and my one is no exception. How does one tell a Nanotyrannus tooth from a dromaeosaur tooth?

[Ridgehiker]

Firstly, glad you didnt iD the tooth to genus. I had my Tyrannosaurid teeth identified by Phil Currie, the world's leading theropod researcher and there is no way of distinguishing a T Rex and Nanotyrannus tooth. If someone sent you a tooth labeled 'Nanotyrannus' then it should be changed to Tyrannosaurid. Nanotyrannus is still a debatable species and only a tooth found in a skull with a certain number of teeth, fused bones, etc. 'might' be Nanotyrannus. You can't go on size. A large Albertosaurus tooth is bigger than many T Rex teeth, etc.

Coincidence. Another member just kindly gave me a copy of an article that distinguishes the various Theropod teeth (put out by Don Brinkman) of the Tyrrell Museum. Don has access to many thousand of teeth to base his study on.

'In general' a Tyrannosaurid tooth is more robust at the base. A Tyrannosaurid tooth often shows more blunt wear at the tip. A Tyrannosaurid tooth usually has similar sized denticles on both the anterior and posterior. However, none of these are fool proof...just accumulated clues. Position in the mouth, erosion, etc. can give a different perception. Supposedly the denticles on a

Tyrannosaurid tooth are more chisel like but I can't tell this....they are more chisel like than other raptors but hard to tell from a dromaeosaur.

In a nutshell, a Tyrannosaurid tooth looks 'fuller' as in if you were to double it in size it would still look hefty....a dromaeosaur tooth if doubled in size would look sleeker.

[Troodon]

Hi Carch

Let me see if I can help but isolated teeth are always a challenge and sometimes its a guess. I attached some images since I always found that a picture is always the way to go.

The first image comes from a new book called Tyrannosaurid Paleobiology edited by Phil Currie & others. In one of the chapter Pete Larson makes the case for Nanotyrannus and its quite a good one. What I really want to show is what a Nano tooth looks like. Its compressed from side to side with serrations basically running down the center of the anterior and interior edge. Pre-max teeth are not serrated and most people typically call they Aublysodon which is not a valid species again according to P. Currie.

The next two images are Dromaeosaur Teeth. The most important characteristic is that they have a twist of the anterior carina. So the serrations start at the midline of the tooth near the tip but soon twists inward toward the lingual surface. The denticles are distinctive in that they are always as high as long. Furthermore they typically have rather rounded tips. Nano's have pointed tips but its sometimes hard to distinguish this feature.

Size is not typically a characteristic when it comes to these teeth. I've see some very large dromie teeth and if you look at the jaw of both these dinosaurs all sizes are present.

Good luck and If you have an ID issue with one of these teeth drop me a line.