Lance Creek Crocs and Therapod?

[gturner333]

I received some matrix from the Lance Creek Formation, Late Maastrichtian, Wyoming, which shares much fauna with the Hell Creek formation. I have found what I think are 4 croc teeth and what I hope is a therapod tooth (piece). The serrations on the therapod (hopefully) tooth is about 5/mm on the basal side and much finer on the other. The picture doesn't show the finer serrations well, but you can feel them by running your fingernail across it. The hash marks are 1mm.

 

Am I right on any of this?

 

[JohnBrewer]

I think you're right but @Troodon and others will help you. 

[FossilDudeCO]

@jpc can help as well!

I think you are right for croc teeth though!

[Troodon]

I believe they are not croc teeth but from the alligator Brachychampsa.

 

That is a theropod tooth what is the length of it.  Cannot figure out your scale 

 

 

[FossilDudeCO]

9 minutes ago, Troodon said:

 

That is a theropod tooth what is the length of it.  Cannot figure out your scale 

 

 

 

Scale is in mm Troodon. about 3mm on that theropod tooth.

[gturner333]

Sorry about that. Fossildude is correct. The hashmarks are 1mm. 

Any guesses as to what kind of therapod?  It would have to be pretty small or is just the tip of the tooth?

[Troodon]

Isolated small theropod teeth are always difficult but my guess is that it's from a Tyrannosaurid.  Serrations compare well to my Nano serrations other than size.   Its probably an infant tooth, my smallest Rex tooth is around 5mm.

 

[gturner333]

thanks for all the help. May it ever be so humble, my first theropod tooth. Pardon my lousy spelling. 

[jpc]

I generally don't ID teeth from the Lance beyond the order level, except mammals.  I can claim laziness or simply satisfaction and too many other things too do.  Yup, theropod and crocodilian teeth.  Troodon... How do brachychampsa and leidysuchus teeth differ?  Can we say that croc teeth are generally pointier?