Weird Hell Creek Tooth - Dromaeosaur premax?

[DinoFossilsUK]

I've just received this weird little tooth from the Hell Creek Formation.  It was sold to me as a Dromaeosaur premax tooth but I have my doubts as it's quite robust.  That said, the other candidate would be a Tyrannosaur and I've never seen a premax tooth with a twist like this.  What's more, the carinae are strange - one has nice crisp serrations (I thought they looked a lot like Tyrannosaur serrations) while the other is smooth (it doesn't look like it ever had any serrations).  Anyone have any idea what it might be?

[DinoFossilsUK]

[DinoFossilsUK]

[DinoFossilsUK]

Oh, I forgot measurements!  The tooth is 19mm long and the serrations are roughly 15 per 5mm.

[fossil_sea_urchin]

@Troodon

[Omnomosaurus]

That is quite an unusual one! Some of those features don't scream tyrannosaur to me at first glance.

 

I would have suggested Dromaeosaurus, as their premax teeth are more robust than other dromaeosaurids, but as far as I'm aware, they're only found in earlier deposits.

 

The unserrated mesial carina is "off", but could it be a juvie tyrannosaur?

[Troodon]

Can you provide the length of the crown excluding the root.  Can you also take a look at the mesial edge and see if any you can see any evidence of serrations. 

 

 The low density count excludes Acherorapter being one of the Dromaeosaurids in the HC.  The other Dakotaraptor fits but the shape of the denticles is more in line with a Tyrannosaurid.  I think its a juvie dentary tooth of a Nanotyrannus but nothing is published to verify my call.

[DinoFossilsUK]

Thanks for your input.  Yes, it's very strange.  I've had a good look and the mesial edge doesn't show any evidence of serrations, it looks naturally smooth.  Dakotaraptor would be awesome, but as you say the denticles look much more like a Tyrannosaur.  The crown without the root is 12mm.  I know that teeth previously assigned to Aublysodon are juvenile premax teeth and they have no serrations.  Is there any possibility the neighboring teeth in the jaw are serrated on only one of the carinae?  Oh, and a slight mistake in my first post, this tooth is from the Lance Creek fm (I know this won't make a difference to the ID).

[Troodon]

Interesting, typically Incisor tyrannosaurid teeth are serrated on both edges.  I dont believe this is a Tyrannosaurid premax tooth.   Dromaeosaurids teeth both premax and Incisor can be found with a smooth mesial edge.  Why identification of isolated teeth is extremely difficult on top of little/nothing being published.   Still not ruling out Dakotaraptor.

[dinosaur man]

I think it might be a dakotaraptor it’s not a archeroraptor because there are no ridges running down the tooth from the apex to the base witch is typical of archeroraptor so I thinks it’s dakotaraptor but I’m no expert.

[DinoFossilsUK]

In that case I'll settle for Theropod indet. with the best candidate being Dakotaraptor.  I plan to sell this one so wanted to get a little advice before passing it on to a new home.  Thanks you all for your help!