Dinosaur Tooth from Austin, TX?

[Jackito]

My loyal assistant and I were exploring in area by the airport in Austin, Texas a couple days ago and we came across a head-sized shell hashy rock. I think we were in Maestrichtian rocks (corsicana marl?)and I found an unusual tooth fragment in the center of the crumbly rock. I also found several small shark teeth and a lot of little shells in the same rock. This tooth is interesting because of the size (1.5 mm long and .7mm) thick and serrated edges.

 

Ok ok... I've come a long way since posting that tooth shaped rock last summer. Since then I've found a lot of teeth in Austin in 4 separate locations but this tooth just seems unusual. The serrated edges and size.. the texture of the outside enamel... Naturally I jump straight to some sort of dinosaur.

 

But it might just be a squalicorax.... but...abelisaur? carcharodontosaurus? Troodon? Gorgosaurus? Or just a shark... What do y'all think?

[Jackito]

Here are the other teeth I found in the same rock.

[Runner64]

The Austin area is in the Eagle Ford Group.  Do you know where you were exactly?  Could be Woodbine Formation.  The fragment does look like the edge of a Theropod carinae to me although no large-bodied theropods are described from the Eagle Ford Group.

[Al Dente]

Interesting piece. Looks too thick to be Squalicorax.

[Troodon]

I'm not sure those are theropod serrations.  Not sure what it is.

Look at those split denticles, to the left,  not typical on theropod serrations.  Also, the uneven texture of the enamel under the carina is also not typical of one.  The inside should also be solid.

 

[garyc]

From the pics it does look like it could be enamel, but could it actually be a piece of crab claw? 

[Jared C]

Again, awesome find Carter. Following with great interest 

[Jared C]

@Uncle Siphuncle have you encountered something reminiscent of this? It’s in the upper Taylor group

[Uncle Siphuncle]

7 hours ago, Jared C said:

@Uncle Siphuncle have you encountered something reminiscent of this? It’s in the upper Taylor group

Hard for me to tell from pics.  The thickness has me open to crustacean matl, but I don’t see the surface detail I’m familiar with.  Looks phosphatized.

[ThePhysicist]

I'm convinced it's Squalicorax, I've seen some chonky ones. 

 

1. The cross section with the strong tapering near the edge is typical for sharks. Here's another Squalicorax for a rough comparison:

 

 

2. The histology (interior tissues) is consistent with that of an osteodont (which Squalicorax is) (G-I in figure from here):

 

 

3. The serrations are consistent in shape with those of Squalicorax, including the "split" serrations (my examples are not as worn):

 

 

One could also argue by Occam's razor that it's just a shark, but I usually eschew that argument for its subjectivity.

[Jared C]

4 hours ago, ThePhysicist said:

One could also argue by Occam's razor that it's just a shark, but I usually eschew that argument for its subjectivity.

Bravo, I'm mighty impressed by your discernment here, as usual. I would have never guessed in a million years that this could be Squalicorax, but your argument convinced me.