Theropod Premax Tooth Hell Creek

[zekky]

I have a 3/8" premax theropod tooth from the Hell Creek formation in Montana, Carter County. Anyone have any ideas whether this is dromaeosaur or tyrannosaur? I know most of the tyrannosaur premax teeth like this do not have serrations, but there are always exceptions. 19 serrations per 5mm.

[ynot]

The experts will want a scale and a serration per millimeter count.

Nice tooth,

Tony

[zekky]

Thanks, forgot to put up the serration count. 19 per 5mm. The dead zone between nano and dromaeosaurs. 

[LordTrilobite]

Very nice tooth. @Troodon will probably have a good idea.

[zekky]

Still not sure

[Micah]

Did anyone every figure this one out?

[Troodon]

My call on this tooth is that its a tyrannosaurid for the following reasons:

 

 The serrates are your classic chisel shaped which is a key feature of tyrannosaurid teeth.  Dromaeosaurid's like Archoraptor have more rounded serrates see illustration.  

 

Although I cannot see the cross-section at the base it looks D shaped which is a characteristic of Tyrannosaurids.  Dromaeosaurid's because of the narrowness of the snout are not.

 

Denticles on the posterior carinae tend to be longer than anterior ones these look the same, see illustration.

 

 

Ref: Dinosaur Systematics by Carpenter & Currie